Which theoretical stage of human development did not exist as a defined life stage until the twentieth century?

   Jean Piaget developed his cognitive -developmental theory based on the idea that children actively construct knowledge as they explore and manipulate the world around them.

   The four stages of Piaget’s theory of cognitive development correspond with the age of the child; they include the sensorimotor , preoperational, concrete operational, and formal operational stages.

   The sensorimotor stage occurs from birth to age 2 and is characterized by the idea that infants ” think ” by manipulating the world around them.

   The preoperational stage occurs from age 2 to age 7 and is characterized by the idea that children use symbols to represent their discoveries.

   The concrete operational stage occurs from age 7 to age 11 and is characterized by the idea that children’s reasoning becomes focused and logical.

   The formal operational stage occurs from age 11 to adulthood and is characterized by the idea that children develop the ability to think in abstract ways.

Key Terms

   deductive reasoning: Inference in which the conclusion cannot be false given that the premises are true.

   object permanence: The understanding (typically developed during early infancy) that an object still exists even when it disappears from sight or other senses.

   Transitivity: The idea that if A is related to B, and B is related to C, then A must be related to C.

   assimilation: The absorption of new ideas into an existing cognitive structure.

Explanation:

the answer is either c or d i think its d

c it has to be i googled it