Question

How plants are the ultimate source of food on the earth ?

Answer 1

As they are produce food by the process of photosynthesis which cannt be done by anyother else.
Solar energy is ultimate energy in the earth from which green plants make their food and provides to other to maintain food chain in our ecosystem.
Plants use chlorophyll and co2 and H2O also in photosynthesis which is a biochemical process and became a cause of life on earth.

Hence plants are the ultimate soyrce of food on earth.

Answer 2

Answer:

the ultimate source of food on earth is green plants