A researcher finds that a particular medication causes rats' memory to improve. A second researcher plans to test this medication with humans diagnosed with Alzheimer's disease. The second researcher is addressing the problem of ____

Children at risk of having a troubled adolescence tend to be:

a) well behaved in elementary school. b) alienated from their parents and have impulse-control issues. c) set up for a life of crime. d) from "good" homes, but who fall in with the wrong crowd.

Children who recover from cancer are ________ more likely to have cancer again

than children in the general population? a. Two times b. Three times c. Four times d. Five times e. Six times