<span>The theory of adjustment to aging that assumes older people are happier if they remain active in some way, such as volunteering or developing a hobby, is called activity theory.</span>
The correct answer here is 2. The IRB must approve the experiment. Whether the experiment is on humans or on animals it must be approved. The IRB will examine the proposed experiment and its methodology in order to see does the experiment meet the ethical standards. Conducting ethical research is of the paramount importance.