A plant having normal enzyme is used as a control by the researchers.
The appropriate control is the plant with normal enzyme which the researchers should use when they study the photosynthetic ability of the plant having mutant enzyme. The researchers can compare different abilities of the normal enzyme plant with the plant having mutant enzyme.
The difference between both mutant enzyme plant and a normal enzyme plant shows which plant is better in growth and photosynthetic abilities so we can conclude that a plant having normal enzyme is used as a control by the researchers.
Learn more: https://brainly.com/question/16303942
