A controlled experiment is a means of carrying out a fair test of a hypothesis. In a controlled experiment, all of the variables that can influence the outcome variable dependent variable) of the experiment are controlled or held constant, except for the test variable (independent variable). Which of the following hypothesis would NOT be tested using a controlled experiment? A. A geologist's hypothesis about how the Grand Canyon formed B. A biologist's hypothesis that use of fertilizer increases the growth of grass C. A geologist's hypothesis that acid rain weathers sedimentary rock more rapidly than eous rock D. A biologist's hypothesis that increases in average temperatures cause an increase in honey bee population