14. describe the function of a control group in an
experiment. [1]
the answer

Explanation:

When you perform an experiment, you can separate the experiments in various groups. Some of those groups will be exposed to controlled changes in one variable, the independent variable.

For example, in you want to measure the influence (effectiveness) of a fertilizer in the crop of tomatoes, you desing experiments with variable amounts of the fertilizer. The amount of fertilizer will be the independent variable. You will need that other conditions remain constant: the kind of soil, the amount of water, the sunlight exposure, among others. Those are controlled variables (not control group)

Then, you can (may be you should) run experiments with a control group. The control group would be a set of tomato plants that will not receive any treatment (fertiizer). So, the results of the experiments with the control group will set a baseline of the growing of the tomato plants when no fertilizer is added. Then, you will be able to compare the results of all the other experiments with the results of the control group to conclude about the influence (effectiveness) of every fertilizer.

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