While some subcultures within the United States are more aggressive than others, _________ is an important factor that may help to explain these differences

Place theory has a difficult time explaining ____.?

a. ?complex tones b. ?low pitches c. ?high pitches d. ?pure tones

A 9- or 10-month-old infant would be most likely to use the correct tool to retrieve a toy if

a. the toy is one of the infant's favorites. c. the toy and the tool are the same color. b. there are no other toys nearby. d. the tool is in close proximity to the toy.