A controlled experiment is a means for 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 hypotheses would NOT be tested using a controlled experiment? A. A biologist’s hypothesis that increases in average temperatures causes an increase in honeybee population.
B. A geologist’s hypothesis that acid rain weathers sedimentary rock more rapidly than igneous rock.
C. A geologist’s hypothesis about how the Grand Canyon formed
D. A biologist’s hypothesis that use of fertilizer increase the growth of grass