Most __________ variables belong to one of four different categories: environmental, instructional, task or activity, or invasive variables

Few developmentalists today believe that the changes of middle age produce a midlife crisis

Indicate whether this statement is true or false.

According to the article Gimme the Ball concerning the development of object permanence, Piaget tested for the presence of object permanence by having a child:

(a) watch as balls of clay were flattened (b) lose sight of an attractive toy which was hidden under a piece of cloth (c) study small models of three mountains (d) all of the above [a, b, and c] were tests used by Piaget in seeking object permanence