Researchers further the biological perspective when they demonstrated that electrical stimulation of the brain could evoke emotional responses in animals. this is an example of how can influence perspectives.

The best answer to the question above would be letter d. The sentence presented which is 'Researchers helped further the biological perspective when they demonstrated that electrical stimulation of the brain could evoke emotional responses in animals.' demonstrates how new discoveries can influence perspectives. 

Balkan nationalism increased tensions between austria and russia

A. radioactive dating