A/C to 10% law ..
100 J of energy is available for lion then ,
10% of x = 100J
x = 1000J
& then , 10% of y = 1000J
y = 10,000
Hence , 10,000J of energy was available to the producer .

Explanation:

A food chain is a sequence of organisms in which each organism feeds on the one below it in the chain. The transfer of energy from one organism to another is known as the food chain. The energy flows in one direction in a food chain and is not cyclic.

The given food chain is:
Grass → Deer → Lion

Primary Producer:
The primary producer in this food chain is grass. Primary producers are autotrophic organisms that produce their own food through photosynthesis. They convert solar energy into chemical energy, which is stored in the form of glucose. Therefore, the grass is the first trophic level in this food chain.

Primary Consumer:
The primary consumer in this food chain is deer. Primary consumers are herbivores that consume the primary producers for energy. Therefore, the deer is the second trophic level in this food chain.

Secondary Consumer:
The secondary consumer in this food chain is lion. Secondary consumers are carnivores that feed on primary consumers for energy. Therefore, the lion is the third trophic level in this food chain.

Energy transfer:
As we move up the food chain, the amount of available energy decreases. Only 10% of the energy is transferred from one trophic level to the next. The rest of the energy is lost as heat or used by the organism for its metabolism.

Calculation of energy:
In the given food chain, 100 J of energy is available to the lion. Therefore, the energy available at different trophic levels can be calculated as follows:

- Energy available to the lion (third trophic level) = 100 J
- Energy available to the deer (second trophic level) = 1000 J (10% of 100 J)
- Energy available to the grass (first trophic level) = 10,000 J (10% of 1000 J)

Therefore, 10,000 J of energy was available to the producer (grass) in this food chain.