Question

the passage below describes an experiment. wesley wanted to grow moss for his terrarium. he usually grew moss on a bed of dirt but wondered what he could add to the dirt to make his moss grow faster. wesley prepared nine moss cultures. in three cultures he mixed moss with only dirt. in three others he mixed moss with dirt and buttermilk. in the final three he mixed moss with dirt and used coffee grounds. he observed how much each moss culture had grown after two weeks. in this experiment, the moss cultures mixed with only dirt were part of ________. a control group an experimental group

Explanation:

In an experiment, the control group is the baseline group that does not receive the experimental treatment. Here, moss with only dirt has no additional substances (like buttermilk or coffee - grounds) added, serving as a reference to compare the growth of moss in the other groups.

Answer:

a control group