Question

the passage below describes an experiment.
image: an air plant displayed on a rock
zoe had six air plants on her desk that were not growing. once a week, she soaked the air plants in water. but she suspected that they needed more water. she wondered if spraying the air plants with water every day in addition to soaking them would help them grow. zoe measured the initial weight of all six air plants. then, for the next month, she continued to soak all of the air plants once a week. she also sprayed two of the plants once every day and two others twice every day. at the end of the month, zoe measured the weights of the plants again.
in this experiment, the plants that were only soaked in water were part of ______.
options:

• a control group
• an experimental group

Explanation:

In an experiment, the control group is the group not exposed to the independent variable (here, daily spraying) to compare with experimental groups. The plants only soaked (not sprayed) serve as the control to see the effect of spraying.

Answer:

a control group