Question

Why do we say energy flow in the biosphere is unidirectional?

Answer 1

The energy flow in biosphere is unidirectional it means that energy flows in one direction only from producer to consumer and does not return back to the producer.
In the Biosphere, the energy is obtained by green plants by photosynthesis . Sunlight is trapped and stored by plants (producers) and the by the process of photosynthesis sun's energy is transformed into chemical energy. The plans are eaten up by herbivores and the herbivores are then eaten up by the carnivores. so the energy stored in plants gets transferred to consumer animals.

Answer 2

As the energy transferred from sun changes into chemical energy and do not return back once used up by the producer, so it is said energy flow in the biosphere is unidirectional