Photosynthesis plays an important role in the environment for several reasons as it helps clean the air because plants use the carbon dioxide in the air for photosynthesis, the plants produce oxygen as a by-product which all humans and animals need to live and it also makes plants grow, providing food for animals that feed on plants. Without plants, the world would quickly become uninhabitable for human and animal life. The oxygen would be used up and there would be no food to feed the animals that humans rely on for food.
The sugars that are in the plants that herbivores eat not only produce energy for the plant itself, but provide energy for the animal that eats it. Vegetables and other plants not only create sugars and carbohydrates for their own use, but also for the use of the consumers. Outside of the consumption of the organisms that use photosynthesis, many of them can be used for their fibers. Cotton is a good example of a plant that uses photosynthesis, but is used for the making of clothing instead of food. Algae also uses photosynthesis to create energy, though it lives in water unlike land plants. Algae provides food for a number of aquatic animals and puts oxygen into the water for ocean dwellers to use.