The passage talks about how both plants and animals show changes in their structure, habits and even mode of reproduction in trying to adapt to their environmental conditions. So, the most suitable title for the passage is option C) Adaptive Divergence. The passage is not about evolution, but about a response to evolution. Hence, option A is wrong. Option B is wrong because the passage is not only about 'our', i.e. human, bodies. The passage cites changes in certain organs as a result of adaptive change, hence, option D as a title would be inadequate to describe the entire passage.