Answer:
[(1)Physical Health], [(2)Social Health], [(3)Mental and emotional health]
Explanation:
By he NIH trying a new drug to help reduce pain associated with sickle-cell anemia, it's an example of an "experiment".
An experiment involves a hypothesis (an educated guess as to what's going to happen) and trying out the hypothesis and finding the solution.
The prevalence of HIV infections remained the same during the year of 1997