For a character trait to evolve in a population, it must a. mutate, affect reproductive success, and cause disequilibrium. b. be heritable, mutate, and affect reproductive success. c. be hidden, vary in the population, and affect reproductive success. d. vary in the population, affect reproductive success, and be heritable.

vary, affect reproductive success, and be heritable

Explanation:

This can be explained by evolution which means change in traits of pollution from one generation to the another. the necessary condition to evolve a trait is vary, affect reproductive success and heritable.

vary signifies change in trait from one generation to another

affect reproductive success: means the change must affect positively the reproductive success or breeding of offspring.

heritable means it should be transferred via genes.