Energy flow is linear / unidirectional in an ecosystem because:-
Only 1% of solar energy falling on leaves of producers get converted into food energy through photosynthesis and is made available to the next tropic level of consumers.
After consumers eat producers a lot of energy is lost to the environment in the form of heat. Energy used is also used by the consumer for digestion, growth, reproduction and other activities.
Only 10% of energy is turned into into its own body and is made available for the next level of consumers[10% Law]
Once energy is taken up by producers from solar energy it cannot be reverted back into solar energy.
Once energy enters a trophic level, it is then not available to the previous trophic level. So little energy is available after every trophic level, and the energy can only go to a higher consumer and not previous consumer.
Solar Energy ⇒ Grass ⇒ Deer ⇒ Lion / Tiger.
Mark as brainliest of helpful..