In the food web the amount of matter remains constant. Matter can change from one form to other in the living beings. In a food web, exchange of matter occurs between organisms of various tropic levels repeatedly and between organisms and their surroundings. Irrespective of change in form and location of the matter, the total amount of matter in food web remains constant.
At the light stage, sunlight is absorbed by the chlorophyll to be converted into Chemical energy. Water will be broken down into H+ ions and OH- ions in the presence of light.
At dark stage, sugars are synthesised from carbon dioxide.
