Which of the following statements about migration is true? a. migration is always from one region to another. b. animals always migrate within a region. c. migration always negatively impacts an ecosystem. d. animals migrate for various reasons.

The correct answer is option a. i.e Migration is always from one region to another. Both hman and animals migrate from one region to another for various reasons. It can be living conditions, employment opportunites, education etc for humans and food, environment changes, breeding etc. for animals.