Experiment to show that sunlight is necessary for photosynthesis - definition. Take a plant with destarched leaf. Leaf is partially covered with black paper on which a design is cut. Expose this plant to sunlight for few hours and perform a starch test with iodine solution.
With the overuse of chemical fertilizers, many lawns now have it to where decomposers can't live. This interferes most directly with the lawn ecosystem to recycle important nutrients. The correct answer is choice number 2.