Which of the following best illustrates a variable interval reinforcement schedule?

__________ and __________ are the two landmark cognitive changes that take place in sensorimotor Substage 4 of Piaget's theory

A) Deferred imitation; make-believe play B) Conservation; centration C) Dual representation; analogical problem solving D) Intentional behavior; object permanence

The principle of natural selection proposes that certain characteristics that ________ will become more prevalent in a species

a. are associated with multiple genetic mutations b. inhibit reproductive behaviors c. increase reproductive success d. impair adaption to the local environment e. reduce reproductive success