(i) Green plants absorb solar energy.
(ii) In the sunlight, they perform photosynthesis in which the food in the form of glucose is synthesized.
(iii) Thus, these organisms can manufacture and utilize the food they make. Hence, they are autotrophs.
(iv) The food they prepare is not only used by them but can be made available to the entire biological world, hence are called producers.
(v) Green plants do not depend on others for food and hence they are called autotrophs.