A bar graph showing a frequency distribution is called a ________

A friend is taking a drug awareness class. One of the things he learns is that LSD, a hallucinogenic drug that produces bizarre sensory experiences, is believed to work because it

a. suppresses the effect of serotonin neurons. b. increases the production of serotonin. c. enhances the effect of serotonin, which is normally excitatory. d. removes serotonin from the body.

During the first two years of life, the number of interconnections between neurons ______

a. decreases dramatically c. increases slightly b. decreases slightly d. increases dramatically