Answer:
Green plants act as producers because they can generate their own food(glucose) by photosynthesis in presence of sunlight.
Step-by-step explanation:
Green plants or producers are placed in the first tropic level of energy pyramid.Animals those intake green plants for energy source are called primary consumers such as grasshopper.
Animals those fed on primary consumers for nutrient source are called secondary consumers or primary carnivores for example frog that eat grasshopper for their energy source.
Animals that fed on secondary consumers for energy source are called tertiary consumers or secondary carnivores.For example snake that eats frog to gain nutrients from the later.