D lowering the activation energy of a reaction.
The cell membrane allows substances to enter and leave the cell and gives the cell structure.
Answer;
D. The birds have different mating seasons.
Explanation;
-Different species of birds have different mating or breeding seasons. Evolution has played a role in adjusting the timing of avian(birds) breeding seasons to maximize the number of young produced. The breeding season depends on a number of factors, for example In the temperate, subarctic, and arctic zones, the overriding factor is the availability of food. This varies across all different species of birds, irrespective of other similarities they may have.
Answer:
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