Question

A scientist is doing an experiment. She wants to find which of the following
treatments is the best way to break down sewage waste. She will test a chemical,
Bacteria X, and Bacteria Y.
What should she use as the control group for this experiment?

A. sewage treated with the chemical

B. sewage treated with Bacteria X

C. untreated sewage waste

D. sewage treated with Bacteria Y

Answer 1

ANSWER:

She should use untreated sewage waste as the control group for this experiment.

EXPLANATION:

• In any experiment, a control group is the independent or isolated group that cannot affect the "outcome of an experiment".

• In this experiment, untreated sewage waste is the control group because untreated sewage wastage cannot affect the outcome of the experiment.

• The sewage waste is being treated with a chemical, bacteria X and bacteria Y all of which will have an impact on the result of the experiment.

• Only untreated sewage waste will not impact the outcome of the experiment.