Final answer:
About 10% of the energy from the grass consumed by a cow is transferred to and stored in the cow's body. The remaining energy is expended in metabolic processes or lost as heat.
Step-by-step explanation:
As a cow grazes on grass, approximately 10% of the grass's energy is transferred to the cow. This is because in a food chain, energy transfer efficiency between trophic levels is typically about 10%. The rest of the energy from the plant is used by the cow for its day-to-day activities and metabolic processes, which are ultimately released as heat.
The majority of the energy is either used by the organism for life processes such as movement, growth, and reproduction, or it is lost to the environment as heat according to the second law of thermodynamics. Consequently, when the cow consumes grass, a significant portion of the energy is not stored in its body. As a result, when a secondary consumer eats the herbivore, they will receive only about 1% of the energy originally present in the plant matter.