The answer is D. The fact that researchers helped further the biological perspective when they demonstrated that electrical stimulation of the brain could evoke emotional responses in animals, is an example of how new discoveries can influence perspectives.
It is an example of how science has advanced and developed during the last centuries, it is also an example of how science works. Researchers are constantly searching for evidence to support or contradict existing theories and knowledge. Advances in technology are an important part of this process, since they make it possible to observe fragments of reality that weren't available before.
