Answer: Because of it's exposure to sunlight, photosynthetic organisms are the bottom of the food chain in the lighted zone
Step-by-step explanation:
In the sunlit zone there is enough sunlight for photosynthesis to take place, photosynthetic organisms like Plankton produce food. The use the light energy from sunlight with carbondioxide and water to produce food and release oxygen. The largest oxygen percentage of the Earth is produced from the ocean(about 90%) which is produced by Plankton. Plankton serve as the primary producers in this zone, many animals also live in this zone because of food availability.