Question 21 (4 points): In a scientific experiment, which of the following is an accurate description of a control group?

Question 21 options:
1. It serves as a basis of comparison with the experimental group.
2. All the variables that remain constant throughout the experiment.
3. A group that allows for the simultaneous testing of multiple variables.
4. The group that is subjected to the factor whose effect is being tested in the experiment.
a) It serves as a basis of comparison with the experimental group.
b) All the variables that remain constant throughout the experiment.
c) A group that allows for the simultaneous testing of multiple variables.
d) The group that is subjected to the factor whose effect is being tested in the experiment.