16. Scientists figured out decades ago that chimpanzees are humans’ nearest evolutionary cousins. They notonly look like us, but share with us some human-like behaviors. They make and use tools and teachthose skills to their offspring. They also have complex social hierarchies and some aspects of culture._______________ All in all, when it comes to DNA, a human is closer to a chimpanzee than a mouse isto a rat.
(A) Their faces are very expressive though look darker and more wrinkled.
(B) Though they can’t form words, they learn to communicate via sign language and symbols.
(C) You need to be a biologist to see how closely chimpanzees resemble humans.
(D) But those few tiny biological changes made all the difference in the world.