Marcy is given her choice of two identical chocolate bars, one of which has been broken into four pieces. marcy chooses the broken candy bar, believing that it has more candy. from piaget's perspective, marcy is showing a lack of indicating that she has not yet completed the transition to the stage of development.

I believe the answer is: conservation; concrete operations

According to piaget, conservation refers to the ability to use logical thinking as a basis for decision making. During the concerete operational stage, people's ability to use rationale thinking had just begun to develop. Which is why people who still haven't finished this stage might had a hard time in separating their emotions and their logic in making a decision.

the telephone is the answer