Question

the passage below describes an experiment. jessica wanted to find ways to save water. she learned that people can reuse greywater, which is water that has been used in sinks, tubs, and washing machines. she wondered if her plants would be less healthy if she watered them with greywater instead of tap water. jessica placed eight potted petunia plants on her windowsill. for three months, she watered four of the plants with greywater and the other four with tap water. at the end of three months, she counted the number of dead leaves on each plant. complete the sentence. in this experiment, the plants watered with tap water were part of a control group an experimental group

Explanation:

In an experiment, the control group is used for comparison. Here, Jessica wants to see the effect of grey - water on plant health. The plants watered with tap water are used as a standard to compare the plants watered with grey - water. So they are part of the control group.

Answer:

a control group