Green plants contain the pigment called chlorophyll in their leaves which acts as a catalyst in the process of photosynthesis. Plants are called autotrophs because they can produce food on their own. They absorb solar energy from the sun, water from the soil through the roots and prepare their own food. But at the same time they act as a source of food for herbivores and omnivores. If plants don't exist, herbivores can't survive and carnivores which feed on the herbivores will also die. Because of the act of producing their own food and because of their presence in the first position in the food chain, they are called producers,
