37. What does “this group” in the fourth paragraph refer to?
(A) Fossil species.
(B) Natural predators.
(C) Big mammals.
(D) Limited competitors.
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統計: A(11), B(5), C(44), D(12), E(0) #2856019
統計: A(11), B(5), C(44), D(12), E(0) #2856019