The independent variable manipulated by Tryon in his artificial selection studies of maze running by rats was

A technician in a sleep laboratory is asked to awaken sleeping adults at random intervals. Which stage of sleep is most likely to be detected when the awakenings take place?

a) Stage 1 b) Stage 2 c) Stage 4 d) REM sleep

Robert Plutchik proposed a model of emotions that suggested the existence of 8 primary emotions

Indicate whether this statement is true or false.