James took two pea plants placing one in a dark closet and the other on a sunny window sill both are located in air-conditioned rooms he then measured the growth of each plant after a week which of the following best describes the purposes of this experiment a. to determine the effect of sunlight on plant growth b. to determine the effect of air-conditioning on plant growth c. to determine the effect of enclosed spaces on plant growth d. to determine the effect of lack of water on plant growth