Use changed assumptions, new calculations and evidence comparisons to support a biological conclusion.
These 22 original public cases include reinforcement and transfer practice. Give a response and explanation before reading feedback, then revise your reasoning. A matching selection or number checks only the stated claim; it does not automatically evaluate the explanation.
Each case retains its first response, latest response, up to three attempts and known feedback exposure through science backups. Explanation drafts are saved too, but remain editable after feedback. Returning to a lesson or importing an older backup does not create a fresh assessment attempt. The cases and keys are inspectable in a browser; this is not a secure examination or independent certification.
The original and expanded sets are summarized separately. Added cases do not alter earlier response records or lesson achievements. Unattempted cases are not evidence of understanding, and these summaries award no course mastery.
0/12 cases attempted; 0/12 first responses match the case keys in this set.
A scale bar 150 pixels long represents 30 micrometers. A cell spans 210 pixels in the same image. What is its length in micrometers?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A neutral permeant solute has 6 mmol in compartment A (2 L) and 6 mmol in B (1 L). Volumes are fixed; there is no pump. Which initial net direction is consistent with passive transport?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
An ideal chamber has gross photosynthetic oxygen production of 9 micromoles/min and respiratory oxygen consumption of 12 micromoles/min. With release defined as positive, what is net oxygen release?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
For ideal complete aerobic oxidation, glucose + 6 oxygen → 6 carbon dioxide + 6 water. Starting with 3 mmol glucose and 12 mmol oxygen, how many mmol of new carbon dioxide can form?
Reinforcement case: this calculation also appears in the respiration lesson. Its earlier response history is retained.
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A diploid cell begins with 10 chromosomes before replication. After normal DNA replication and completed meiosis I, how many DNA molecules does each daughter cell contain? Count chromatids, not chromosome sets.
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
Two conditions have the same coding DNA sequence and the same measured RNA abundance, but one has twice as much protein. Which claim is supported by those observations alone?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
In an Aa × aa cross with Mendelian segregation, each offspring has probability 1/2 of being aa. Assuming independent offspring, what is the probability that the next two offspring are both aa? Give a percentage.
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
In a small population, an allele disappears over several generations. No survival or reproduction measurements are available. Which conclusion is justified?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A teaching controller has target amount 100 units and current amount 120. It removes 0.25 × (current − target) during the next step, with no new input. What is the next amount?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
Six quadrats along a path contain an average of four plants each. They were selected for easy access. What can be concluded without further sampling assumptions?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
One tray receives light condition A and another receives B. Each holds ten plants; all plants are measured daily. Which criticism matters for a causal comparison of light conditions?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
Producers make 1,000 kJ available over a stated interval. Primary consumers receive 20% of that amount, and secondary consumers receive 15% of the primary-consumer amount. How much reaches secondary consumers?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
0/10 cases attempted; 0/10 first responses match the case keys in this set.
Two learners measure the same frozen onion micrograph with the same valid scale calibration. They report chords of 120 and 140 pixels, but used different endpoints on a diffuse wall band. What should they do before treating this as variation between cells?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
An artificial phospholipid bilayer separates solutions with different concentrations of a charged solute. The solute crosses very slowly despite the gradient. Which explanation is consistent with membrane structure?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
Newly made labeled protein reaches the Golgi, where its amount rises, while little label appears outside the cell. Which claim is best supported by these observations alone?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A growing DNA strand ends with A opposite a template C. Under a proofreading mechanism, which sequence of actions can restore complementary pairing before extension resumes?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A rooted tree has root children P and ancestor A. A has children Q and ancestor B. B has children R and S. Your group contains Q and R. Which additional sampled taxon or taxa are required to include every descendant of their most recent common ancestor, without adding more distant taxa?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
An ecosystem begins with 80 g nitrogen inside the chosen boundary. Harvest exports 9 g, deposition adds 4 g, and decomposers transfer 15 g from detritus to soil inside the boundary. With no other exchanges, what total nitrogen remains inside?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
In an ideal steady circuit, blood flow is 3 L/min, oxygen content entering tissues is 180 mL O₂/L, and returning content is 120 mL O₂/L. There are no other oxygen exchanges or accumulating stores. How much oxygen must the lungs add per minute to restore the incoming content?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
Ideal complete aerobic oxidation uses 6 mmol oxygen per mmol glucose and produces 6 mmol carbon dioxide per mmol glucose. A vessel starts with 2 mmol glucose and 9 mmol oxygen. After the limiting reactant is exhausted, how many mmol of carbon atoms remain in unreacted glucose? Each glucose molecule contains six carbon atoms.
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A relationship hypothesis is supported by an existing DNA alignment. Which proposed follow-up adds new biological observations, rather than only reanalyzing that same file?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
In a fictional kidney-cell experiment, hormone exposure fails to increase water permeability. Directly increasing the abundance of the same functional water channels restores permeability under matched conditions. What conclusion is best supported?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
For a mismatch, state which mechanism or assumption you overlooked before retrying. For a match, answer the further challenge without copying feedback. Current explanation drafts may include later learning; they are not evidence of what you knew before exposure.
A reviewer should examine these explanations alongside the seed-growth project and a new problem or dataset. Public answers alone do not establish independent reasoning or practical technique. Science backup export includes the current explanation text for review and revision.
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