Answer:
a. The researcher follows the same group of people over the course of 40 years. The researcher also measures the number of the people's taste buds throughout the 40 years. The researcher finds that as people grow older, their sense of taste diminishes and their number of taste buds decreases.
Explanation:
You should follow the same people over a period of time, so you get an idea how their feel for food varies. There is a variation.
The correct answer is:
a. The researcher follows the same group of people over the course of 40 years. The researcher also measures the number of the people's taste buds throughout the 40 years. The researcher finds that as people grow older, their sense of taste diminishes and their number of taste buds decreases.