__________ help(s) explain why fragile X syndrome is expressed only when it is passed from the mother to the child

What term refers to helping behavior that is performed voluntarily for the benefit of another person, with no anticipation of reward?

a) altruism b) collectivism c) interdependence d) humanitarianism

Attention-deficit/hyperactivity disorder has been linked to irregularities in the way which of the following neurotransmitters operates in the brain?

a. dopamine b. serotonin c. acetylcholine d. GABA