Eighteen-month-old Lawrence's favorite pastime is to roll balls around the house. He particularly likes to roll balls under the furniture and run to where he thinks they might emerge. This is an example of a

A correlation is considered to be zero if:

one variable increases while the other decreases. there is no instance of a negative correlation. both variables increase together. no connection between the variables is seen.

Intimacy is best defined as

affiliation. generativity. sexuality. self-esteem.