Why is it necessary to place a plant in the dark before starting an experiment on photosynthesis? Explain.

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Solution

The only way to observe of occurrence of photosynthesis in a plant is to identify the production of starch. For that, it is necessary to test for the presence of starch coming from photosynthesis during the experiment. The previously formed starch should not interfere while examining. In order to prevent the previously formed starch from interfering, we remove the starch and it is done by keeping the plant in dark. When the plant is in dark, the photosynthesis does not occur and the stored starch is used up.

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(a) What aspect of photosynthesis was being tested ?

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