An expimenter wants to know if listening to classical music will help people to solve more math problems. The expimenter has a group of people come in for the study in the morning, and plays them classical music while they solve math problems. The expimenter then has a group of people come in for the study in the afternoon, and has them solve math problems with no music playing. What did the expimenter fail to do

to provide common conditions of research

Explanation:

In simple words, the common conditions of research must be provided when that particular condition can be a distorting factor to the results obtained. In the given case, the two subjects groups were tested on two different times. There is a high chance that the morning group would have performed better than the afternoon ones.

Hence, it will be seen as a failure of the experimenter to test the groups in two different times.

answer; i believe that the correct answer is (tabula rasa);

mammals. mammals of the piedmont region live in several habitats such as wetlands, fields and forests. raccoons live across the state including the piedmont. they've adapted to environmental changes, including the loss of natural habitat.