According to Freud, what do the "defense mechanisms" defend against?

With regard to sound, a pure tone consists of several sub-waves with different frequencies

Indicate whether this statement is true or false.

Which of the following is NOT a criticism of Piaget's theory?

A) Cultural plays a large role in the attainment of formal operational thought. B) Young children are less cognitively advanced than he believed. C) There may be a stage or quality of thinking beyond formal operations. D) Some adolescents and adults never reach the formal operational stage.