Which is the best explanation for why Mesopotamians built canals? a. They needed a way to control the flooding.
b. They needed a way to control the surplus.
c. They needed a way to control the river’s flow.

Identify the example of when situation and time are key to assessing risk of harm in a research study: a study on the efficacy of a behavioral intervention for smoking cessation involves both adults and teenagersasking women if they have had an abortionresearch on the prevalence of hiv-infected individuals in communitiesa survey about sexually transmitted diseases