問題詳情

Question 41-50Naturalists and casual observers alike have been struck by the special relationshipbetween squirrels and acorns (the seeds of oak trees). Ecologists, though, cannot observeThese energetic mammals scurrying up and down oak trees and eating and burying acornswithout wondering about their complex relationship with trees. Are squirrels dispersers(5) and planters of oak forests or pesky seed predators? The answer is not simple. Squirrelsmay devour many acorns, but by storing and failing to recover up to 74 percent of them(as they do when seeds are abundant), these arboreal oodents can also aid regenerationand dispersal of the oaks.Their destructive powers are well documented. According to one report, squirrels(10)destroyed tens of thousands of fallen acorns from an oak stand on the University ofIndiana campus. A professor there estimated that each of the large while oaks hadProduced between two and eight thousand acorns, but within weeks of seed maturity,Hardly an intact acorn could be found among the fallen leaves.Deer, turkey, wild pigs, and bears also feed heavily on acorns, but do not store them,(15)And are therefore of no benefit to the trees. Flying squirrels, chipmunks, and mice areAlso unlikely to promote tree dispersal--- whose behavior of caching (hiding) acorns belowThe leaf litter often promotes successful germination of acorns --- and perhaps blue jays,Important long-distance dispersers, seem to help oaks spread and reproduce.Among squirrels, though, there is a particularly puzzling behavior pattern. Squirrels(20)pry off the caps of acorns, bite through the shells to get at the nutritious inner kernels,and then discard them half-eaten. The ground under towing oaks is often littered withthousands of half -eaten acorns, each one only bitten from the top. Why would any animalwaste so much time and energy and risk exposure to such predators as red-tail hawks onlyto leave a large part of each acorn uneaten? While research is not conclusive at this point,(25)one thing that is certain is that squirrels do hide some of the uneaten portions, and theseacorn halves, many of which contain the seeds, may later germinate.
41. What does the passage mainly discuss?
(A) The ecology of oak trees
(B) Factors that determine the feeding habits of Squirrels
(C) Various species of animals that promote the dispersal of tree seeds
(D) The relationship between squirrels and oak trees

參考答案

答案：D
難度：簡單0.8
統計：A(0),B(0),C(1),D(4),E(0)

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