Final answer:
The control group in an experiment serves as a baseline for comparison to the experimental group, and does not receive the experimental manipulation.
Step-by-step explanation:
The part of an experiment in which all conditions are kept the same and you compare your data against is the control group. This group serves as a baseline for comparison, controlling for chance factors that might influence the results of the study by holding such factors constant so that the experimental manipulation—being exposed or not exposed to the independent variable—is the only difference between groups. The control group does not receive the experimental manipulation, thus allowing researchers to measure the effect of the independent variable on the dependent variable by analyzing the differences, if any, between this group and the experimental group.