Answer:
A constant is a quantity that does not change. Although you can measure a constant, you either cannot change it during an experiment or you choose not to change it. In contrast, an experimental variable is the part of an experiment that is affected by the experiment. In a scientific experiment, the controlled or constant variable is one that does not change. In an experiment designed to test the effect of different light sources on plants, other factors that affect plant growth and health, such as soil quality and irrigation, must remain constant.
Explanation:
