By what age do toddlers usually have a vocabulary of about 200 words?

Freud believed that the infant becomes emotionally attached to the mother during this time because she is the ____________________ satisfier of the infant's needs for food and sucking

Fill in the blank(s) with correct word

A ________ is a means of adapting schemes that involves stumbling onto a new experience caused bythe baby’s own motor activity, then trying to repeat the event again and again

A) sensorimotor reflex B) circular reaction C) mental representation D) goal-directed behavior