What is the name of the single-subject research design that introduces an independent variable at different times for different behaviors to see if changes in behavior coincide with manipulation of the independent variable?

Which of the following statements about tracking is false?

A. Teaching quality is more or less the same in different tracks. B. Students who are tracked tend to socialize mainly with peers from the same academic group. C. Tracking can cause hostility between students in different tracks. D. Tracking procedures often discriminate against minority and poor students.

Parkinson's disease produces tremors and muscular rigidity because of damage to

A. acetylcholine neurons in the parasympathetic branch. B. dopamine neurons in the nigrostriatal pathway. C. norepinephrine neurons in the locus ceruleus. D. the blood-brain barrier.