The term __________ refers to the tendency to help others who are in need, even when there is not likely to be a reward for helping.

Experiments with the visual cliff show that

a. human infants are aware of shape constancy. b. human and animal depth perception is entirely learned. c. perceptual grouping does not begin until a baby is from six to fourteen months old. d. human infants perceive depth by the age of six months.

The chromosomal make-up of a normal male is ______; the chromosomal make-up of a normal female is ______

YY; XY XX; XY XY; XX YY; XX