The power of the brain arises from the cooperation of large numbers of neurons connected together in

The term "male menopause" is sometimes used to refer to

the sudden loss in fertility in a middle-aged man. the sudden drop in testosterone that generally occurs at about age 50. a dip in testosterone in response to anxiety or sexual inactivity. impotence when a man is aware of his wife's menopause.

A psychologist has generated a hypothesis. Now,

a. it becomes a theory. b. researchers are bound to accept it as valid. c. research is needed to verify the if-then link. d. researchers are likely to move on to other hypotheses.