Which perspective is being practiced when a psychologist focuses on the activities a person is engaging in, and not the thoughts or feelings the person has?

No this statement in not correct as when a psychologist focuses on the activities a person is engaging in, then the psychologist is not only focusing on this but that person’s feeling and thought as well.

Explanation:

Yes, is not that when a psychologist focuses on the activities a person is engaging in, he (psychologist) is not focusing on this perspective but he is also focuses on feeling and thoughts of that person’s as well.

A psychologist focuses on the normal and abnormal mental situation, emotional, and social processes experimenting with perceptual, cognitive and behavior, and observing, explaining, how a person relate to each other and their environments.

In this subject each and every aspect of the observer is important to study in which scenario the person different and relating themselves in the existing environment.  

elastic potential energy

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."