For C, it is given that seeds buried deep underground cannot germinate.
It is given in the passage that rodents bury in shallow underground caches.
If rodents were only looking for food storage, they could have very well used deep underground caches.
However rodents deliberately use shallow underground caches because they want the seed to germinate.
Therefore, it is effectively strengthening the proposal that seed-burying functions not only as food storage but also as a way to promote new plant growth.
Bunuel
Certain rodents bury seeds in shallow underground caches even when food is plentiful, and they rarely recover all the seeds they store. Researchers hypothesize that seed-burying functions not only as food storage but also as a way to promote new plant growth around the rodents’ home areas, thereby boosting their future food supply.
Which of the following, if true, most strongly supports the hypothesis?
(A) Rodents are more likely to bury seeds in areas where plant density is low than in areas with abundant vegetation.
(B) Some of the seeds buried by rodents are occasionally dug up and eaten by other animals.
(C) Seeds buried in deep caches are often too far down to germinate.
(D) Rodents tend to bury more seeds during years when rainfall is scarce.
(E) In areas where rodents are absent, most seed dispersal occurs via wind and insects.
GMAT Club Official Explanation:
(A) Correct. Burying seeds preferentially in spots where plants are scarce aligns with the hypothesis: the rodents appear to be “planting” where growth is most needed, behavior that would boost future food supply in their home range.
(B) Irrelevant. Other animals eating some cached seeds merely shows a potential cost of scatter-hoarding; it neither confirms nor refutes the idea that rodents bury seeds to foster later plant growth.
(C) Undermines. If seeds placed in deeper caches rarely germinate, the act of burial cannot reliably promote vegetation, directly challenging the proposed secondary purpose.
(D) Trap. A surge in seed-burying during drought could signal forward-looking “farming,” but it could just as easily reflect a simple need to stockpile when fresh food is scarce; without more context, the datum offers only weak, equivocal support.
(E) Irrelevant. Knowing that wind and insects handle dispersal where rodents are absent tells us nothing about the rodents’ motives in areas they do inhabit and therefore sheds no light on the hypothesis.