What do children do in the formal-operations stage that they do not do in the concrete-operations stage?

A) understand that an object maintains its weight and volume after a change in its shape
B) reach around a barrier to retrieve a hidden object
C) develop a systematic strategy for solving a problem
D) distinguish between appearance and reality

Formal-operations Stage

The final stage of Piaget's theory of cognitive development, starting around age 12, where abstract, logical, and systematic thinking becomes possible.

Concrete-operations Stage

The stage in Piaget's theory of cognitive development, from ages 7 to 11, when children gain a better understanding of mental operations and can think logically about concrete events.

Systematic Strategy

An organized, methodical plan of action designed to achieve a specific goal or solve a particular problem.