Question #N1013

The passage describes a study that was conducted to test the effects of a new type of fertilizer on crop growth. The researchers found that the new fertilizer increased the yield of crops in a test plot. However, the researchers also found that the yield of crops in the control plot, which was not treated with the fertilizer, also increased. What is the most likely reason why the researchers included a control plot in their study?

In the study described in this passage, the control plot was most likely included to
A. make sure that the new fertilizer was the only factor that contributed to the increase in crop yield.
B. provide a baseline against which the results of the test plot could be compared.
C. determine the average yield of crops in the area where the study was conducted.
D. test the effectiveness of the fertilizer on a variety of different types of crops.