Answer:
C
Step-by-step explanation:
The complete question: A student conducts an experiment to see how music affects plant growth. The student obtains four identical plants. Each one is potted in the same type of soil and receives the same amount of sunlight and water each day. Plant A listens to classical music for three hours each day. Plant B listens to rock music for three hours each day. Plant C listens to country music for three hours each day. Plant D does not listen to any music at all. In the experiment described in the scenario, which group represents the control group? A. Plant B B. Plant A C. Plant D D. Plant C?
The control group here would be plant D.
Control groups are usually used to minimize the effects of extraneous variables in the course of experiments and to ensure that the differences observed in different experimental groups are due to the effects of the independent variables.
In this case, all the plants were exposed to music except the control group because the aim of the experiment is to measure the effects of music on plant growth. Any difference in growth observed between those exposed to music and the control group can reliably be considered to be due to the music.
The correct option is C.