Approximately what percent of American adolescents below the age of 19 live with at least one of their biological parents?

When the presence of others enhances one's performance of a well-learned task, we call this effect the _______ phenomenon

a) social facilitation b) law-of-numbers c) spectator d) self presentation

Habituation and recovery make learning more efficient by

A) helping us anticipate what event is about to happen next. B) focusing our attention on those aspects of the environment we know least about. C) helping us generalize newly learned behaviors to unfamiliar contexts. D) influencing the occurrence of stimulus events in the environment.