Using Gibson’s and Walk’s visual cliff test, researchers determined that infants who have just begun to crawl will crawl out over the “deep” side, whereas those who have been crawling for at least two weeks avoid it. Researchers hypothesized that the action of crawling allows infants to figure out how to use __________

Sound waves are amplified in the middle ear by tiny bones called the hammer, anvil and the stirrup, which serves to push against the __________ and set fluid in the cochlea in motion

a) tympanic membrane b) oval window c) basilar membrane d) auditory nerve

Strong stressors that occur suddenly and affect many adolescents simultaneously, such as tornadoes and floods, are known as ________

Fill in the blank with the appropriate word.