In one study, adolescents who smoked cigarettes were about twice as likely as nonsmokers to later use marijuana. For this reason, cigarettes have been referred to as

Clifton is a sophomore who is a starter for his high school varsity football team and is larger than most of the other boys in his class. Clifton was probably a

a. late maturing adolescent. c. normally maturing adolescent. b. early maturing adolescent. d. natural athlete.

Neurons have a distinct ability to communicate with other cells using a cluster of fibers called __________

a) nucleus b) myelins c) synapses d) dendrites