A. males rarely participate in infant care
The keyword here is "area per volume" which is available in both cases. Besides capillaries are smaller than arteries they have in total more area as there are many vessels of then. The More the area/volum, the less the velocity
the actual CORRECT answer is change.
So,
The environment needs to [change] in order for natural selection to occur.
Don't worry i took the test trust me!
