Question

a yes, because although they vary, both hare and lynx populations persist for decades.
b no, because both hare and lynx populations are varying up and down.
c no, because the number of hares almost goes to zero during several years of the study.
d yes, because the hares will eat plants and keep their populations under control.

Explanation:

To determine the correct answer, we analyze the options based on population persistence. Option A states that despite variations, both hare and lynx populations persist for decades, which aligns with the concept of stable cycles in predator - prey relationships (even with fluctuations, the populations remain over time). Option B is incorrect because population fluctuations (up and down) don't mean they don't persist. Option C is wrong as a temporary near - zero for hares doesn't mean the population doesn't persist overall (and lynx also persist). Option D's reasoning about hares eating plants is not relevant to the persistence of both hare and lynx populations.

Answer:

A. Yes, because although they vary, both hare and lynx populations persist for decades.