During the word explosion, a child's vocabulary goes from about ________ words to __________ of words at age 5

Baby Lakota is shown a ball that is then hidden under a cover. What must Lakota do to retrieve the ball?

A) Lakota will need to recall the location of the ball. B) Lakota must coordinate "pushing aside" and "grasping" schemes to retrieve the ball. C) Lakota will not be able to retrieve the ball until she is in Substage 6 of the sensorimotor period. D) Lakota will have trouble retrieving the ball until she no longer makes the A-not-B error.

Definitions that use abstract or general terms are considered to be

a. useful definitions. b. working definitions. c. theoretical definitions. d. operational definitions.