Between 3 and 18 months of age, the brain's weight increases by what percent?

The concrete operational stage of cognitive development is

A. the second of Piaget's stages B. the third of Piaget's stages C. the fourth of Piaget's stages D. the last of Piaget's stages

Around what age do children begin to regard relational aggression as a more mature form of social manipulation than physical aggression?

A) Seven years old B) Nine or ten years old C) Eleven or twelve years old D) Fourteen years old