Controlled processes require attention; it is often difficult to carry out more than one controlled process at a time

As compared to earlier times, physical development during middle childhood is best described as:

a. "Bodies are stronger and immune systems are better developed." b. "Bodies are much more susceptible to disease and illness." c. "Bodies are much pudgier with a higher body mass index." d. "Bodies are much weaker and immune systems are stressed and taxed."

Low to moderate doses of amphetamine-related drugs generally

a. increase virtually all motor activities b. enhance performance on tasks requiring sustained attention c. enhance performance most dramatically when the person is fatigued d. only b and c