A senator must be how old to serve?

In the example of an ABA design in which a teacher wanted to reduce a child's self-stimulatory behavior, the independent variable was

A) the number of times the child hit herself. B) the number of days it took to reduce the self-stimulatory behavior. C) the attention given to the child when she engaged in self-stimulatory behavior. D) the psychologist's presence in the classroom.

Population growth slowed considerably during the 1980s—less than 1 percent growth in 1987-88. What is an explanation for this statement?

a. Extensive outmigration took place after the oil bust from 1984-1986. b. Texas's decreasing averages in areas like job and income growth discouraged people from migrating. c. There was a rise in worldwide demand for oil during the 1980s, causing native Texans to relocate as jobs opportunities expanded worldwide d. The political culture in Texas tended to be moralistic in nature at the time and discouraged outsiders from making Texas their new home