As cognitive development and emotional self-regulation advance in middle childhood, sibling conflict tends to decline.

Researchers are interested in the ventricles in the brain because

a. they become enlarged in some disorders. b. they fill with cerebrospinal fluid. c. they are often found to be absent in people with severe mental disorders. d. they connect the forebrain, midbrain, hindbrain, and cerebellum.

According to Seligman and Peterson, the human strength of "courage" is expressed by the positive traits of

a. curiosity, open-mindedness, and perspective. b. persistence, integrity, and vitality. c. fairness, leadership, and citizenship. d. forgiveness, humility, prudence, and self-control.