Question

quiz
question 4 of 10
in a controlled experiment, scientists investigate a single
choose one option
a placebo.
b control.
c variable.
d cell.

Explanation:

In a controlled experiment, the key is to investigate how a single factor (variable) changes while keeping other factors constant. A placebo is a fake treatment, a control is the group not receiving the treatment, and a cell is a biological unit. So the correct option is about the variable being investigated.

Answer:

C. variable.