On a few occasions, Jack's mother gave him candy to keep him quiet when she took him to the doctor's office. Now every time Jack goes to the doctor's office, he asks his mother for candy. This is an example of

A researcher goes to great lengths to ensure that the proportion of males and females in his study matches the proportion of males and females nationally. He is selecting a ______ sample

a. random b. controlled c. biased d. representative

What behavior has an astonishing range of damaging health effects, including causing cancer of the lungs, mouth, throat, esophagus, larynx, bladder, kidney, cervix, pancreas, and stomach?

It causes cardiovascular disease and leads to heart attacks. It also causes strokes and causes vision, hearing, taste, and smell to decline more quickly. a. overeating b. excessive drinking c. smoking d. lack of exercise