Gregory is a six-month-old baby boy. He is learning about his environment through touching things, putting things in his mouth, and scooting around on the floor. According to Piaget, Greg is in the ________ stage of cognitive development

By ______ years of age, children fully understand object permanence

Fill in the blank with correct word

When two stimuli are associated to produce a reflexive response in an organism, that animal (or person) has demonstrated __________ conditioning

a. classical b. aversive c. operant d. associative