Mildew is a fungus that grows in wet areas and can slowly grow from microscopic to large stains in showers and sinks. Researchers are studying different sprays that could be used to slow down the growth of mildew. They set up different showers that are exactly the same and expose them each to water with the same microscopic amount of mildew. They then spray some showers with mildew-preventing sprays and observe how fast mildew grows over time.

Which shower would most likely be the control group in this study?

A. the shower sprayed with many test sprays

B. the shower not exposed to any mildew at all

C. the shower not sprayed with any mildew-preventing spray

D. the shower sprayed with a test spray that is already known to work

The correct answer is C. The shower not sprayed with any mildew-preventing spray

Explanation

According to the fragment of the statement, it can be affirmed that the correct answer is "C. The shower not sprayed with any mildew-preventing spray". This is explained by the fact that, as the author reports, "Mold is a fungus that grows in humid areas and can grow slowly from microscopic to large stains in showers and toilets", so it can be affirmed that its growth is over time. and its exposure to humidity. Therefore, if you have several test showers, it would be necessary to compare how much does mold grow? How long does it take to grow? and for this, it is necessary to take a control group, that is, a group of reference showers regarding the growth of mold under normal conditions without having applied any aerosol, to compare and know which aerosol is the most effective.

the answer to this question is a