本题目来源于试卷: Continuity and Change D.10 Natural Selection，类别为 IB生物学
[单选题]
The graph shows the nu 0 )vlnfc-d.aef x ,k7u u iquj lt6.tau(in,p(-otelk-2),yw mber of female African elephants (Loxodonta africana) born without tusks in Gorongosa 6utu(t,i- 2y)ilnp wt,luj. -kaqe o( National Park. How does natural selection explain the trend shown in the graph?
A. Elephants broke their tusks while fighting, and their offspring were born without tusks.
B. Poachers hunted elephants with tusks, resulting in increased survival of elephants without tusks.
C. Elephants born without tusks are better fighters so survived better.
D. Mutations resulting in no tusk formation started to happen more often.
参考答案: B
本题详细解析:
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