Answer: 1. a change in an individual's body in response to changes in environmental conditions
Explanation:
An adaptation can be defined as any alteration or change that occurs in the structure and function of the organism that results due to natural selection. An adaptation generally occurs when the organism is exposed to an unfavorable environment.
The adaptation makes an organism better suited to survive in an unfavorable environment. The changes in the environment favor the changes in the body of living individuals.