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AP07 · SCIENCE THROUGH EVIDENCE

AP Environmental Science

A complete authored AP Environmental Science pathway: 76 original destinations across nine topic categories and cumulative evidence defense, with retained investigation plans, mixed written tasks and a staged watershed project. Authored coverage is distinct from learner mastery and supervised fieldwork.

This is the course outline. Open a unit to choose a lesson; every lesson opens on its own page. Explanations and experiments live inside those lesson pages.

Preparation and course boundaries

Preparation: Ratios, percentages, area and time units, graph reading, basic chemistry and ecological vocabulary. Essential distinctions are explained in each lesson.

Course outcome: Interpret environmental systems using explicit boundaries, quantitative evidence, controlled comparisons and qualified solution claims. Authored-category coverage is separate from independent mastery and hands-on fieldwork.

All lessons are directly accessible. Reused foundation explanations are identified where relevant; completing a different course does not award this course's evidence. The 76 registered lessons keep separate predictions, captures, practice responses and reflections.

Ecosystem processes and evidence8 lessons

Explain biome constraints, carbon/nutrient/water cycling, productivity and trophic energy; evaluate a perturbation without confusing conservation with causation.

Biodiversity and ecological change7 lessons

Compare diversity, services, colonization, tolerance, disturbance, adaptation and succession using explicit evidence and uncertainty.

Population processes and demographic evidence8 lessons

Analyze recruitment, survivorship, density feedback, resources, age structure, fertility and migration without deterministic forecasts.

Earth systems and resource evidence8 lessons

Explain tectonic, soil, atmospheric, watershed and climate mechanisms using explicit geometry, budgets and limits of inference.

Land and water use: compare solutions and displaced impacts9 lessons

Evaluate agriculture, extraction, urbanization and forestry through stated boundaries, resource balances, alternative mechanisms and qualified sustainability claims.

Energy resources, conversion and consumption8 lessons

Compare resource mechanisms, useful-energy boundaries, time-dependent supply and environmental tradeoffs without conflating power, energy, renewable supply or lifecycle impact.

Atmospheric pollution: sources, transformations and controls8 lessons

Distinguish emissions, chemistry, mixing and exposure; audit pollutant-specific controls and interpret logarithmic quantities without unsupported safety or compliance claims.

Aquatic and terrestrial pollution: pathways, effects and evidence9 lessons

Trace pollutant sources and fates; compare treatment and prevention while interpreting toxicological and population evidence under declared boundaries.

Global change: atmospheric mechanisms, oceans and biodiversity9 lessons

Distinguish ozone chemistry, greenhouse energy and ocean carbonate pathways; evaluate counterfactual evidence and conservation responses with explicit uncertainty and tradeoffs.

Cumulative evidence and revision2 lessons

Defend a cross-system watershed recommendation with retained original plans, quantitative contrasts, competing explanations, human critique and unfamiliar transfer.

Investigation portfolio

Keep predictions before comparison, complete raw records and units, explain competing models and test a changed case. Supplied and simulated data are labeled in each lesson. A saved notebook is not proof of experimental technique or correct reasoning.

Atmospheric mechanisms and counterfactual evidence

Evidence to retain: Balance a catalytic cycle and top-of-atmosphere ledger, separate metric changes from actual emissions, and compare synthetic observed/counterfactual residuals with physical attribution requirements.

Boundary: No atmospheric forecast, current GWP inventory, refrigerant handling, ultraviolet exposure or full climate-model calculation.

Ocean heat and carbonate comparison

Evidence to retain: Retain two heat/expansion balances and carbonate-ratio comparisons; state fixed area, coefficient, bicarbonate and activity assumptions. Explain why biological outcomes need additional evidence.

Boundary: Original ideal column and stipulated equilibrium ratio, not measured ocean profiles, full seawater speciation or organism experiments.

Conservation mechanisms and unintended effects

Evidence to retain: Test event-order and immigration sensitivity, derive repeated local persistence, and compare equal-area core habitat. Propose a monitored solution with non-target, connectivity and distributional tradeoffs.

Boundary: Not a species extinction forecast, official conservation classification, wildlife handling, organism introduction or land-management authorization.

Watershed load, oxygen and heat comparison

Evidence to retain: Retain paired source/retention cases, close a capped oxygen inventory and a weighted heat balance; design measurements that discriminate loading, dilution and mixing explanations.

Boundary: Synthetic parcels and assigned removal fractions. No contaminated-water sampling, discharge-site entry, nutrient release or heating experiment.

Contaminant fate and response inference

Evidence to retain: Separate matched response differences, persistence and trophic concentration, endpoint midpoints and incidence ratios. Preserve denominators and propose a controlled alternative explanation.

Boundary: No real chemical doses, organism exposure, pathogen culture, medical diagnosis or identifiable health-data collection.

Source, chemistry and mixing comparison

Evidence to retain: Construct a same-pollutant emission inventory, compare supplied precursor interventions, close an atmospheric box and separate carbon/product masses from particle concentration. Propose weather and measurement controls for a real inference.

Boundary: Synthetic supplied observations and stipulated response table, not current air-quality data, a chemical forecast or an exposure experiment.

Control pathways and nonlinear quantities

Evidence to retain: Close tracer and removal balances, distinguish pH from free-ion amount and total acidity, and add independent sound intensities rather than logarithmic levels. Explain a control limitation and a safe evidence design.

Boundary: No pollutant release, chemical neutralization, industrial operation, asbestos handling, loud-sound exposure or personal safety/medical/regulatory judgment.

Demand and useful-output comparison

Evidence to retain: Retain per-person/total, fuel/useful-output and power/time comparisons; reconstruct conversions and identify a denominator or behavior change that reverses a ranking.

Boundary: Fictional populations, fuel factors and tariffs; no current national ranking, product recommendation, financial advice or full lifecycle assessment.

Resource timing and environmental boundaries

Evidence to retain: Compare parent inventories, non-overlapping carbon terms, annual versus chronological output, hydraulic power and sequential conversion. Name omitted exposure, ecology, counterfactual and storage constraints before recommending an option.

Boundary: No real isotope handling, energy-system construction, hydrogen operation or plant safety certification. All numerical ledgers are original synthetic models.

Food-production boundary comparison

Evidence to retain: Retain paired area/input, delivery/withdrawal, survival/frequency and feed/edible-output calculations. Predict a reversal when the denominator or system boundary changes; design a replicated discrimination between competing impacts.

Boundary: Assigned teaching comparisons, not measured crop response, pesticide instructions, diet advice, animal care or actual irrigation engineering.

Shared resources and extraction decisions

Evidence to retain: Close each material ledger, distinguish stock from annual change and propose a monitoring/governance response with an uncertainty trigger. Request ecological information not supplied by production mass alone.

Boundary: No field access, harvesting, wildlife contact, mining or tree cutting. One-year synthetic balances are not sustained-yield estimates.

Urban runoff and footprint evidence

Evidence to retain: Calculate weighted runoff, retained and unretained volumes, then compare total and per-person resource-demand equivalents. Design a before/after comparison with matched storms and a reference site.

Boundary: No local drainage approval, groundwater-safety determination or official ecological-footprint assessment; capture does not automatically imply infiltration or pollutant removal.

Boundary motion and soil evidence

Evidence to retain: Convert a relative speed/time displacement, close a soil-thickness budget and locate mineral fractions on an original accessible texture diagram; distinguish texture from measured hydraulic properties.

Boundary: No earthquake timing or actual soil erosion/infiltration prediction; no field sampling or hazardous site access required.

Atmospheric and watershed mechanism audit

Evidence to retain: Compare pressure/rotation recipes, event volume, solar-angle and dry-parcel ledgers; explain a regional climate or ENSO claim using omitted-process evidence.

Boundary: Quantitative formulas are declared teaching models, not a weather forecast or current ENSO classification. The custom ledgers mix units only in a labeled table, not a misleading common-axis graph.

Life history, survival and population feedback

Evidence to retain: Compare equal-recruitment cases, reconstruct conditional versus cumulative mortality, calculate instantaneous density feedback and close a resource budget.

Boundary: Expected recruits and derivatives are not exact future census counts. Strategies and K depend on conditions; no physical population manipulation is requested.

Demographic denominators and scenarios

Evidence to retain: Calculate age dependency, age-specific TFR, natural increase and migration-inclusive change; compare percentage and absolute rates across two scenarios.

Boundary: Invented aggregates, not current national statistics. Dependency categories do not measure actual work or value; no coercive population-policy inference is justified.

Diversity, services and island comparisons

Evidence to retain: Retain contrasting richness/proportion and colonization/extinction cases, reconstruct index and flux calculations, then audit a service proposal for omitted and duplicated benefits.

Boundary: Indices and partial monetary balances do not determine conservation priority or distribute benefits fairly by themselves.

Responses through time and across conditions

Evidence to retain: Compare controlled response cases; calculate a reference-adjusted contrast and one-generation selection change; propose evidence distinguishing acclimation, selection and historical legacies.

Boundary: Synthetic curves are not measured tolerance limits, field causal estimates or inevitable succession forecasts.

Four connected matter budgets

Evidence to retain: Draw each boundary, label stocks/fluxes and units, close two changed-case balances, identify internal transfer and explain a limitation.

Boundary: Annual assigned rates; no claim to measured global fluxes, fertilizer response or safe long-term yield.

Mixed assessment and cumulative project

Open the retained response and project workspaces. Practice, saved work and independently reviewed proficiency remain separate.

Mixed assessment and retained reasoning

These 61 course-specific public tasks are practice, not a secure examination. Each retains up to three immutable written responses, known feedback exposure before each response, and human rubric critiques. Drafts remain editable. No text-length check or self-reported review certifies correctness, independence, laboratory skill or mastery.

1. Retained original investigation plan: ecosystem

A proposed fertilizer addition is claimed to increase both annual atmospheric uptake and stored ecosystem carbon. Before viewing a worked balance, draw atmospheric/lateral boundaries, specify respiration and export measurements, predict a case with uptake but declining stock, and design a replicated comparison. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

2. Retained original investigation plan: biodiversity

Two disturbed sites differ in time since disturbance and residual soil. Design an original comparison of recovery, ecosystem service and species roles without declaring one snapshot a universal succession sequence. Specify richness, abundance, productivity and a causal versus indicator-species test. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

3. Retained original investigation plan: populations

A broad-base population and narrow-base population have the same current total. Plan how to test different future growth claims without treating working-age dependency or current TFR as an exact forecast. Specify age bands, survival, migration and uncertainty. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

4. Retained original investigation plan: earth

A land manager attributes high runoff solely to soil texture. Plan a comparison that separates texture, compaction, slope, ground cover and storm intensity. State measurement units and identify a result inconsistent with the texture-only explanation. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

5. Retained original investigation plan: landwater

A farming proposal claims fertilizer, irrigation and land clearing necessarily increase sustainable production. Design an original audit with nutrient and water budgets, erosion controls, ecosystem costs, yields and affected communities. State safe virtual boundaries. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

6. Retained original investigation plan: energy

Two energy options deliver nominally identical service. Plan a comparison that tests equal service, efficiency, capacity versus actual generation, lifecycle emissions, water and habitat impacts. Predict a boundary change that could reverse a ranking. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

7. Retained original investigation plan: air

A lower indoor tracer concentration is presented as proof that all indoor hazards have been eliminated. Plan a source/pathway/control comparison distinguishing particles, chemical gases and radioactive progeny; specify limits of the mixing model. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

8. Retained original investigation plan: pollution

A food-web concentration ratio is used to claim a pollutant caused a reproductive decline. Design an original study separating persistent transfer, dose/exposure, observed effect, species susceptibility and competing causes. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

9. Retained original investigation plan: global

A short local cold interval and a single model mismatch are used to reject a long-term climate explanation. Plan a comparison of time scale, proxy/measurement uncertainty, natural and combined forcing, ocean heat and ecological outcomes. Submit the first plan before opening public feedback; record prior exposure and assistance. After a critique, retain a distinct revision and changed-case prediction rather than overwrite the original.

Course-specific review criteria

  • Explicit original question, boundary and competing mechanism
  • Independent observations, replication and measurement units
  • Prediction that could challenge the claim
  • Safety, exposure and synthetic-versus-field evidence declared

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

10. Challenge an apparent watershed improvement

A treatment stream changes from 4 mg/L at 1000 m³/day to 2 mg/L at 3000 m³/day. Comparison flow remains 1000 m³/day and concentration changes 3→2 mg/L. Calculate concentration and load change contrasts. Design a test of the claim that an intervention reduced nutrient delivery and improved ecosystem health.

Course-specific review criteria

  • Correct volume/mass conversion and both contrasts
  • Separate measured quantity from causal effect
  • Independent repeated sites/times and ecological endpoints
  • No drinking-water or fieldwork certification

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

11. Revise a boundary-sensitive recommendation

Reference operation is 150 MWh/year at0.4 t CO₂/MWh, with assigned other emissions zero. Alternative is125 MWh/year at0.5 t/MWh plus10 t/year other lifecycle emissions. Compare totals and identify two non-emissions outcomes requiring separate evidence. What changes if equivalent service is not verified?

Course-specific review criteria

  • Reference60 and alternative72.5 with units
  • No arbitrary addition of unlike outcomes
  • Explicit service/counterfactual assumption
  • Conditional recommendation and reviewer transfer

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

12. Two atmospheric processes, two balances

In the stated Cl/ClO cycle, four cycles consume ozone and atomic oxygen while regenerating chlorine. Give net reactants/products. Separately incoming solar300W/m² has25% reflection and outgoing longwave220. Find net accumulation and explain why ozone depletion and enhanced greenhouse warming are not the same mechanism.

Course-specific review criteria

  • Cancel catalytic intermediates without consuming catalyst overall
  • Balance oxygen atoms
  • Distinguish ultraviolet absorption from infrared energy balance

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

13. Change an emission, not merely a metric

An inventory has80tCO₂ and4tCH₄ with a stipulated common-horizon factor25tCO₂e/tCH₄. Reduce methane emissions25%. Calculate before/after totals and percentage reduction. Contrast changing only the factor to20 at unchanged emissions.

Course-specific review criteria

  • Apply the reduction only to methane mass
  • Retain actual gas and equivalent units
  • Separate reporting convention from physical change

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

14. A closer residual is evidence, not the entire proof

A supplied30-year packet observes0.9°C change; candidate natural-only and combined models give0.3 and0.8. Calculate residuals and observed change per decade. Name two evidence requirements for real attribution and distinguish one mitigation from one adaptation action.

Course-specific review criteria

  • Use observed-minus-modeled signs
  • Normalize time correctly
  • Identify uncertainty/physical fingerprints and distinct policy pathways

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

15. Heat uptake does not calculate carbonate saturation

A100m column over1m² warms1.5K, using density1000kg/m³,heat capacity4000J/(kgK),expansion coefficient0.0002/K. Calculate heat uptake and expansion rise. Separately pH8.2, held bicarbonate1.5mM and stipulated K₂10⁻⁹M give what carbonate concentration? Explain why neither predicts coral mortality.

Course-specific review criteria

  • Keep column heat and height dimensions separate
  • Use logarithmic pH and declared fixed bicarbonate
  • Name missing biological/full-chemistry evidence

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

16. An apparent stable count can hide an open boundary

A fictional introduced population starts200, grows by multiplier1.25, then20% is removed;30 immigrants arrive afterward. Find end count and explain why introduction alone does not establish invasiveness or justify releasing a biological control organism.

Course-specific review criteria

  • Respect event order
  • Include immigration
  • Require harm evidence and non-target risk evaluation

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

17. Equal area is not equal persistence

One1km² square and four equal squares each use100m edge depth. Calculate total core in each. Separately annual local persistence0.95 across four independent years gives what persistence/loss probability? Explain why neither result assigns an official species status.

Course-specific review criteria

  • Convert area to side before subtracting two edges
  • Multiply independent probabilities
  • Distinguish geometric and local-probability evidence from full conservation assessment

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

18. Separate retained load from dilution

A fictional watershed has point input30kg/day, diffuse input150kg/day and20% retention of diffuse input only. Flow is3millionL/day. Calculate downstream load and completely mixed concentration; explain why wetland retention does not prove destruction.

Course-specific review criteria

  • Preserve which source is retained
  • Convert kg to mg before concentration
  • Name storage/release and hydrology limits

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

19. A baseline changes the percentage

Two supplied endocrine-response groups change80→100 and120→140 normalized units. Calculate absolute and relative changes. A separate fictional curve100d²/(m²+d²) has d6,m3. Calculate response and explain why this is not automatically LD50 or human risk.

Course-specific review criteria

  • Use each matched baseline
  • Distinguish endpoint response from lethal dose
  • State missing exposure and population evidence

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

20. Do not use one model to invent another endpoint

A2000L closed parcel starts at7mg/L oxygen and has assigned aerobic demand5mg/L. Separately8m³/s at18°C mixes with2m³/s at28°C under equal heat capacities and no losses. Calculate remaining oxygen and mixed temperature. Can the temperature result predict mortality?

Course-specific review criteria

  • Convert oxygen stock and demand consistently
  • Use flow-weighted heat balance
  • Distinguish thermodynamic mixing from biological response

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

21. Residue mass is not a trophic concentration

A residue begins120mg and experiences two half-lives. Separate tissue measurements are prey0.4 and predator1.2mg/kg on the same basis. Calculate remaining residue and concentration ratio; identify what is missing for total burden.

Course-specific review criteria

  • Apply repeated halving
  • Compare like tissue concentration units
  • Do not create mass or infer individual risk

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

22. Add the recovery process boundary

Baseline waste1200kg/day is reduced10% before generation. Half of generated waste is collected for recycling, with80% process yield; all rejects join disposal. Calculate generation, product and total disposal. Separately wastewater flow2millionL/day at150mg/L demand undergoes20% then90% remaining removal. Find final demand load/concentration.

Course-specific review criteria

  • Use nested denominators
  • Include recycling rejects in disposal
  • Keep wastewater organic demand separate from pathogen/nutrient claims

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

23. Ratios require comparable follow-up

Group A has20new cases among400initially at risk; B has15among150 over the same stated interval. Calculate both incidence proportions, A/B ratio and percentage-point difference. Explain why an environmental cause is not established.

Course-specific review criteria

  • Use at-risk denominators rather than raw cases
  • Distinguish ratio from percentage points and prevalence
  • Identify confounding or ascertainment alternatives

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

24. A cleaner factor is not the entire inventory

Mobile activity is 4000 km/day at 1.5 g/km; a fixed source emits 3 kg/day of the same pollutant. A policy reduces only mobile emissions by 20%. Calculate before/after totals and percent reduction; state why an ambient concentration does not follow.

Course-specific review criteria

  • Convert grams before combining
  • Apply the reduction to the correct source
  • Separate emission flow from concentration and exposure

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

25. Interpret a changed precursor response

A matched synthetic packet has ozone baseline 70 ppb, tested NOx-reduction response 65 and VOC-reduction response 45. Calculate differences and explain why the result is not a permanent classification of a city.

Course-specific review criteria

  • Use matched within-packet contrasts
  • Distinguish concentration difference from percent
  • Require chemical/weather/transport context

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

26. Mass, mixing and independent particle evidence

An atmospheric box covers 2 km², has mixing height 250 m and retains 15 kg of one pollutant. Calculate mean µg/m³. Separately, 5 kg fuel carbon has 60% conversion to CO₂. Calculate product and unresolved carbon without equating either to particle concentration.

Course-specific review criteria

  • Convert area, volume and mass
  • Preserve carbon versus CO₂ units
  • Do not add or equate mass and concentration

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

27. Two control balances, two different boundaries

A 150 m³ inert-tracer room exchanges air twice hourly, with outside 5 µg/m³ and source 300 µg/h. Find steady concentration. Separately, a 200 kg/h pollutant stream has sequential removal 75% then 60% of remainder. Find final flow and overall removal.

Course-specific review criteria

  • Use volume×exchange as airflow
  • Add the outdoor background
  • Apply second removal to the remainder

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

28. Logarithms do not replace the underlying quantity

Compare ideal free-H⁺ amounts in 3 million L at pH5 and 1 million L at pH4. Separately, combine four equal independent 60 dB sources at one receiver. Explain what neither calculation establishes.

Course-specific review criteria

  • Convert pH to ideal concentration before multiplying volume
  • Add sound intensities before logarithms
  • Distinguish free ions from total acidity and sound level from dose

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

29. An improving average with rising total use

A fictional population grows from 3 to 4 million while annual per-person demand falls from 30 to 25 GJ. Calculate both totals in PJ and explain two reasons why the figures alone do not establish improved welfare or efficiency.

Course-specific review criteria

  • Convert millions of GJ into PJ
  • Distinguish per-person and total change
  • Request comparable services and accounting basis

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

30. Carbon intensity is not the whole useful-output comparison

Deliver 200 GJ useful energy from A at 25% efficiency and 70 kg CO₂/GJ fuel, or B at 50% and 90. Find fuel inputs and direct CO₂. Explain why the direct ranking is not a complete environmental recommendation.

Course-specific review criteria

  • Divide useful output by efficiency
  • Apply consistent input-based factors
  • Name upstream methane, extraction and non-CO₂ omissions

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

31. Separate decay and carbon time boundaries

An isolated parent inventory begins at 640 million nuclei; four half-lives pass. Separately, a biomass packet releases 60 t CO₂, has 45 t additional uptake, 8 t supply emissions and 12 t distinct land-stock loss. Calculate both outcomes, then explain why neither a waste-safety claim nor automatic biomass neutrality follows.

Course-specific review criteria

  • Use repeated fractional decay
  • Avoid double-counting carbon terms
  • Distinguish inventory/CO₂ arithmetic from risk and counterfactual claims

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

32. Equal annual energy is not continuous supply

An installation has 4 MW capacity and 25% annual capacity factor. Compute annual MWh and mean MW. A four-hour demand trace is [2,2,2,2] MWh, while supply is [0,4,0,4]. Explain why equal totals do not show storage-free matching.

Course-specific review criteria

  • Use 8760 hours with power units
  • Distinguish capacity factor from conversion efficiency
  • Identify chronological deficits and storage constraints

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

33. Power, heat and carrier accounting

A hydro turbine has flow 3 m³/s, head 40 m, density 1000 kg/m³, g=9.81 m/s² and efficiency 75%. Find electric kW. Separately, 200 kWh input passes through hydrogen-production 60%, delivery 80% and fuel-cell 50%. Find returned electricity and distinguish the mechanisms.

Course-specific review criteria

  • Convert hydraulic watts to kW
  • Multiply sequential efficiency fractions
  • Do not apply hydraulic equations to chemical conversion or geothermal heat

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

34. Lower power with changed service time

A 20 W device runs five hours/day; a 10 W alternative runs six, for 365 days. Compare annual energy and savings at assigned tariff 0.20 units/kWh. An extra cost 14.60 units is proposed; compute simple payback and name limitations.

Course-specific review criteria

  • Convert Wh to kWh
  • Use each schedule rather than equal hours by assumption
  • Separate arithmetic payback from financial recommendation

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

35. A full stock can conceal depletion

A common resource begins at 150 t, adds 15 t/yr and has five users taking 4 t/user/yr. Find final stock and an equal-share ceiling that matches the stated regeneration. Explain why that ceiling is not automatically a safe policy under uncertain growth.

Course-specific review criteria

  • Close the annual stock balance
  • Distinguish annual extraction from remaining stock
  • Propose monitoring and a revision trigger

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

36. Less land, more input

A crop target is 120 t/yr. System A yields 6 t/ha/yr with 90 kg N/ha/yr; B yields 8 with 140. Compare required area and total nitrogen input. Separately compare feed ratios 4 and 6 kg/kg live gain when edible fractions are 40% and 80%.

Course-specific review criteria

  • Use a fixed-output crop boundary
  • Calculate total rather than only per-hectare input
  • Convert live-gain denominator to edible output

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

37. Withdrawals and returns

A crop target requires 900 m³ delivered. Methods are assigned 50% and 75% delivery efficiency; usable returns to the same source are 700 and 100 m³. Compare withdrawal and withdrawal-minus-return. What extra evidence prevents calling this a complete basin balance?

Course-specific review criteria

  • Invert the efficiency
  • Subtract returns within a common boundary
  • Identify timing, quality, storage and expansion limits

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

38. Fewer pests, greater resistance share

An initial cohort has 900 susceptible and 100 resistant pests. Compare survival pairs (20%,80%) and (40%,80%). Compute total survivors and resistant frequency. Explain why neither alone determines an IPM response.

Course-specific review criteria

  • Use surviving total as denominator
  • Distinguish count and frequency
  • Require pest identity, damage, threshold and non-target evidence

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

39. Production is not impact equivalence

Recover 2 t metal at 2% grade and 50% recovery under the dry-solids model. Separately, a wild fish stock begins at 800 t, adds 60 and loses 90 to harvest; a farm gains 80 t at feed ratio 1.25. Calculate each ledger without transferring farm fish into the wild stock.

Course-specific review criteria

  • Apply grade and recovery separately
  • Close independent wild and farm balances
  • Name missing mineralogy, feed sourcing and ecological information

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

40. Runoff control does not erase land conversion

A 1000 m³ storm has coefficients 0.9 impervious and 0.2 pervious. Compare 20% impervious with no retention against 80% impervious with 60% runoff retention. Then compare footprint equivalents 2.5/person×1000 people and 2.0/person×1400.

Course-specific review criteria

  • Weight surface fractions
  • Apply capture to generated runoff
  • Distinguish per-person and total demand and name omitted impacts

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

41. A transform is not a motionless boundary

A fictional pure-transform boundary has relative speed 80 mm/yr for 1 million years. Find lateral and boundary-normal displacement, then explain why these do not predict an earthquake date.

Course-specific review criteria

  • Convert millimetres to kilometres
  • Separate normal and lateral components
  • Identify unmodeled strain/friction/time evidence

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

42. Soil stock and texture are not a fertility certificate

Initial soil 200 mm forms at 0.1 and erodes at 0.5 mm/yr for 100 years. Separately, a mineral sample has sand 40%,silt 40%,clay 20%. Find final thickness and interpret the composition without claiming a crop yield.

Course-specific review criteria

  • Balance formation and erosion over time
  • Locate three fractions summing 100%
  • Separate texture from structure,chemistry and productivity

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

43. Compare pressure and heating evidence

In the isothermal model p=101.3 exp(−z/H), set z=H. Find pressure fraction and explain why this does not show temperature declines continuously through the stratosphere.

Course-specific review criteria

  • Use dimensionless exponent
  • Distinguish pressure from temperature
  • Identify ozone absorption and model limitation

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

44. Event volume is not peak discharge

Compare 1 km² catchments receiving 50 mm at 20% runoff and 30 mm at 40%. Calculate volumes and explain what else is needed to compare flood peaks.

Course-specific review criteria

  • Convert depth×area
  • Apply the assigned fraction
  • Request timing,hydrograph and drainage evidence

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

45. Separate climate mechanism from a forecast

A dry 20°C parcel rises 2 km under 9.8°C/km. Separately,a tropical ocean packet is+1°C relative to 25°C. Calculate both values and explain why neither gives a local rain amount.

Course-specific review criteria

  • Calculate dry cooling and anomaly separately
  • Identify saturation/latent heat and coupling/duration limits
  • Avoid merging independent models

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

46. Equal recruitment is not equal lifetime success

Compare 10 offspring/adult at 10% survival with 2 at 50%. Both begin with 100 adults. Find expected recruits and name two missing variables for lifetime population growth.

Course-specific review criteria

  • Multiply offspring by survival
  • Distinguish one episode from a lifetime
  • Identify adult survival and reproductive timing

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

47. Keep cohort denominators consistent

An original cohort has 60% survival through one interval and 80% conditional survival through the next. Calculate final survival and cumulative mortality.

Course-specific review criteria

  • Multiply survival fractions
  • Use the original cohort for cumulative mortality
  • Do not add percentages with different denominators

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

48. Distinguish a derivative from resource persistence

At r 0.2/year,N 1500,K 1000 calculate the logistic instantaneous rate. Separately, a resource begins 5000 units, renews 1000/year and supports 300 users consuming 4 each/year. Find final stock and explain why the remaining stock does not prove sustainability.

Course-specific review criteria

  • Include density multiplier and negative sign
  • Close resource balance with units
  • Avoid exact next-year population or indefinite stock claims

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

49. Compare fertility and age structure

A simplified period schedule has 80 and 60 births/1000 women/year across two 15-year age bands. Calculate TFR. Explain why two populations with this same TFR can have different annual birth totals.

Course-specific review criteria

  • Multiply by band widths
  • Retain births/woman units
  • Use actual numbers of women at each age for annual births

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

50. Natural increase differs from total growth

A fictional population 200000 has birth 25,death 15 and net migration−5 per 1000/year. Find natural-increase percent, total-change percent and annual headcount change. State a doubling-time limitation.

Course-specific review criteria

  • Convert per 1000 to percent
  • Include migration only in total change
  • State rate-constancy and age-structure limitations

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

51. Distinguish community influence from an indicator

A consumer is5% of individuals. Both treatment and reference begin with20 species; after exclusion treatment has8 and sham reference19. Calculate the adjusted richness contrast and explain why a separate organism merely correlated with pollution is not automatically a keystone.

Course-specific review criteria

  • Calculate a reference-adjusted effect
  • Distinguish causal influence from diagnostic association
  • Request replication and artifact checks

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

52. Compare succession stocks and net production

An early stage has GPP40,producer respiration10,heterotroph respiration20. A later stage has200,100,95 respectively, all g C/m²/yr; assume no lateral carbon transfers, harvest, fire or other omitted inputs/losses. Calculate NPP and net ecosystem production; explain whether greater standing biomass requires greater net accumulation.

Course-specific review criteria

  • Separate producer and heterotroph respiration
  • Do not equate a stock with a rate
  • Keep stage comparison conditional

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

53. Resolve conflicting diversity rankings

A has four equal species shares. B has a focal share 0.85 and five others sharing 0.15 equally. Calculate richness and 1−sum(p²), and explain why the rankings can disagree.

Course-specific review criteria

  • Normalize proportions
  • Distinguish richness from an abundance-sensitive index
  • Request sampling and conservation-context evidence

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

54. Audit a service subtotal

A fictional 30 ha project costs 300 per ha/yr. Exposure is 1000 per ha/yr and estimated avoided fraction is 40%. Find partial net annual benefit and break-even fraction. Explain why a property premium based on the same flood reduction may not be additive.

Course-specific review criteria

  • Use compatible area and time units
  • Separate net from gross
  • Identify double counting and distributional omissions

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

55. Infer turnover without changing richness

For a 100-species pool compare c/e=0.2/0.1 and 0.4/0.2 per year. Calculate expected richness and balanced immigration in both. Explain why equilibrium does not freeze identities.

Course-specific review criteria

  • Solve the rate balance
  • Retain flux units
  • Distinguish expected count from observed integer census

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

56. Separate temporal change from a disturbance contrast

Both sites begin at 100. Reference ends 90; treatment ends 110. Calculate naive and reference-adjusted change, then name an assumption that could fail.

Course-specific review criteria

  • Preserve sign
  • Subtract the reference change
  • State parallel-counterfactual-trends limit

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

57. Distinguish adaptation from need

Initial inherited haploid variant frequency is 0.1, relative contribution 2 versus 1. Calculate next frequency. Explain why an individual physiological response does not establish inherited adaptation.

Course-specific review criteria

  • Normalize relative contributions
  • Describe across-generation selection
  • Distinguish acclimation and omitted stochastic processes

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

58. Resolve a seasonal-average claim

Two synthetic sites each receive 1200 mm/yr. Site A receives rain equally in two six-month seasons; Site B receives 80% in the wet season. Potential demand is 75 mm/month. Calculate deficits without soil carry-over, then explain why these data cannot uniquely identify biomes.

Course-specific review criteria

  • Compute monthly rain before deficits
  • Preserve annual and monthly units
  • Name additional climatic and biological evidence

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

59. Distinguish a carbon sink from a stock increase

An original ecosystem begins at 500 g C/m². Annual uptake 200, total respiration 140, lateral import 10 and export 100 share g C/m²/yr units. Determine final stock and net atmospheric exchange. Is a declining stock inconsistent with atmospheric uptake?

Course-specific review criteria

  • Show full boundary balance
  • Distinguish stock and flux
  • Do not label every export atmospheric CO₂

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

60. Detect a nitrogen form fallacy

At fixed external terms, internal nitrification increases by 10 kg N/ha/yr. Predict changes in NH₄-N, NO₃-N and total mineral N; then explain how denitrification differs.

Course-specific review criteria

  • Conserve nitrogen atoms
  • Track forms separately
  • Declare atmospheric and organic boundaries

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

61. Challenge the universal 10% shortcut

NPP 20000 kJ/m²/yr sends 60% to grazing. Two consumer steps each transfer 5%. Calculate herbivore and predator production and compare with NPP 10000 and 10% per step.

Course-specific review criteria

  • Use the allocated path rather than all NPP
  • Apply efficiency twice
  • Avoid asserting a population forecast

Include calculations with units, source or dataset provenance, assumptions, competing explanations and limitations as relevant. The draft is saved but is not a locked response until submitted.

0/3 responses retained. No recorded feedback exposure for this task version. Earlier versions may already be familiar. Public inspectability still prevents certification of unfamiliarity.

Retain a criterion-by-criterion human review

Reviewer identity and role are declarations, not authenticated credentials. Unsaved review fields below are lost on navigation. Review every criterion with an exact quotation, calculation or evidence citation and a next step.

Watershed decision portfolio — full-course evidence defense

Evaluate an original fictional watershed proposal combining a farm buffer, energy-service change and habitat restoration. Reconstruct evidence across ecosystem cycles, biodiversity/populations, soils/runoff, land use, energy, pollution and global change. Retain original plans and a first report before critique; public examples are practice, not reserved evaluation.

  1. Freeze the original causal plan

    Submit the nine course-specific original-plan responses before their public feedback. Select a central watershed claim, map sources/stocks/flows/exposure/endpoints, define the service and affected groups, and record all prior exposure or assistance.

    Evidence to retain: Retained first-plan records, system diagram, competing explanation, uncertainty and safe measurement proposal.

  2. Build and independently reconstruct the evidence

    Use at least one investigation from each of the nine categories. Save paired captures where controls exist, reconstruct at least three different balances with units, and explain why unmeasured biological or social outcomes do not follow automatically.

    Evidence to retain: A nine-category crosswalk with capture references, equations, explicit omitted mechanisms and source URLs/date checked.

  3. Write the first decision report

    Compare at least two alternatives under equal-service assumptions. Include concentration versus load, a land/water or nutrient budget, energy/climate boundary, habitat/population inference, pollutant pathway and a distributional tradeoff. State missing evidence and a falsifying prediction.

    Evidence to retain: Immutable first report separating synthetic results, proposed observations and conditional recommendation; completed cumulative written tasks.

  4. Use critique and changed evidence

    Ask a human reviewer to challenge the strongest inference and supply a changed boundary or unfamiliar case. Retain critique and revise once, explaining exactly which claim changes and why. Keep unsuccessful predictions visible.

    Evidence to retain: Reviewer critique, revision rationale and retained unfamiliar assignment/prediction/response with exposure and assistance declarations.

Project review criteria

  • Correct conservation, denominators and units
  • Mechanisms across all nine topic categories
  • Causal alternatives and uncertainty
  • Explicit evidence provenance/exposure and retained revision
  • Fair service boundary and distributional tradeoffs
  • Safe proposed work and separately verified real fieldwork
  • Independent human assessment of unfamiliar transfer, not automatic mastery

Retain raw-data identifiers, provenance, units, prior predictions, methods, calculations, competing explanations and safety boundaries. State explicitly when data are simulated, supplied or genuinely observed. This saved text cannot verify a real experiment; do not invent measurements or completed supervised work. Maximum 12,000 characters; retain larger evidence files separately and cite them.

A nonempty report is only a saved submission. First and revised reports remain separate and cannot be overwritten. A critique of the first report is required before retaining one revision.

Fresh transfer direction

A reviewer supplies a genuinely unfamiliar watershed with changed rainfall timing, flow, soil retention, electricity intensity and habitat connectivity. Predict before consulting feedback, then defend which earlier conclusions transfer and which require new evidence. A renamed public packet is not independent transfer.

A human must supply the actual new task, evidence and conditions before the learner responds. The transfer-direction text is not itself an unseen assessment. Use the retained assignment form after the first project; exposed public task identifier: expanded-public:ap-environmental.

Science backups preserve each course's separate responses, exposure, rubric reviews and project history. Older backups do not reset attempts or erase known exposure. Divergent same-version immutable responses and incompatible same-version project histories are rejected rather than silently replaced; preserve both files for review.

Sources and boundaries
  • College Board AP Environmental Science framework: Current course structure and science practices; full nine-unit clause/action reconciliation checked 31 October 2026. Source-label anomalies are disclosed in the current audit, not silently normalized.
  • Course at a glance: 99 topic positions across nine units, taught in 74 category destinations plus two cumulative destinations; topic labels are supplemented by the exact current clause/action audit.
  • Fall 2026 framework clarifications: Current Fall 2026 replacements applied to nutrient cycling, adaptation, population change, soil texture, irrigation/meat and fracturing; checked 31 October 2026.
  • Course Audit laboratory and resource requirements: Minimum 25% hands-on inquiry/fieldwork, retained evidence, textbook and resource requirements checked 31 October 2026. This authored app does not establish performed time or institutional authorization.
  • All 76 planned destinations, nine original-plan tasks, 52 mixed written tasks and the cumulative watershed project are authored. Actual independent assessment and supervised inquiry/fieldwork are separate requirements.
  • Public feedback and editable explanations are practice, not independent assessment.
  • Computational activities do not satisfy the required 25% hands-on inquiry/fieldwork time, equipment access, recent textbook or institutional AP authorization.
  • No physical collection, animal manipulation, fertilizer addition or chemical handling is requested.

Original LearnAI explanations and tasks use the references for scientific scope. Any attributed dataset or image has its own declared provenance. Laboratory or field activity requires an appropriate educator-approved protocol; no hazardous real-world operation is required by the guided path.

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