Nutrients enter a cell up the concentration gradient by the process of active transport.
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.
When the sun produces energy, it consumes hydrogen and then produces Helium. Nuclear fusion is the source of all energy, generated by the sun. The Sun, either converts hydrogen to helium or makes helium nuclei from protons, and also, the Sun converts mass to energy.
D is what he probably thought but it all depends on genetics so if they did stretch out the kid would still have a short neck to it would be A