A group in which all conditions are the same as the experimental group except the independent variable is not applied.

• A. Independent Variable
• B. Control Group
• C. Negative Control
• D. Positive Control

Answer: (B)

Establishing a baseline for comparison is the key idea here. In any experiment you want to know what happens when you don’t apply the variable you’re testing, so you set up a group that receives all the same conditions as the treated group except the independent variable is omitted. That setup defines the control group, which provides a reference point to see whether the observed effects in the experimental group are due to the variable being tested rather than other factors.

The independent variable is the factor you intentionally change, so it isn’t a group itself. A negative control is still a control condition, but it’s specifically used when you expect no effect and want to rule out false positives; the scenario doesn’t imply that expectation. A positive control is included to demonstrate that the system can produce a known positive result, which is not what’s described here.