Compared to advertisers who communicate using repetition with variation, advertisers who use simple repetition are more likely to run the risk of advertising wearout

The period of the embryo occurs during the ____ weeks of pregnancy

a. first and second b. third through eighth c. ninth through 12th d. 13th through 20th

Potentially problematic variables that can lead to alternative explanations for the results of a study are called ___ variables.

a) independent b) confounding c) dependent d) experimental