Question

according to the passage, what is the most important reason for controlling
a. to ensure that the results are due to the independent variable alone.
b. to use more materials.
c. to make the experiment take less time.
d. to make the experiment easier to conduct.

Explanation:

In an experiment, controlling variables helps isolate the effect of the independent variable on the dependent variable. This ensures valid results. Using more materials, reducing time, or ease - of - conduct are not the main reasons for controlling variables.

Answer:

A. To ensure that the results are due to the independent variable alone.