Apply 10% rule u got ur answer...
1,000,000 has 10% get 1,00,000 joule ...

So, "100000" joule that is option B is correct...

$$Hope it's help... $$

Calculation of Energy Available for Primary Producer Level in an Ecosystem

Incident Solar Energy: 1,000,000 joule

Step 1: Gross Primary Production

The energy available for primary producer level is calculated by the Gross Primary Production (GPP). GPP is the total amount of solar energy that primary producers capture and convert into organic compounds through photosynthesis.

Assuming an average efficiency of 1%, the GPP can be calculated as:

GPP = Incident Solar Energy x Efficiency

GPP = 1,000,000 joule x 0.01

GPP = 10,000 joule

Step 2: Net Primary Production

The energy available for primary producer level is further reduced by respiration and other metabolic processes. The remaining energy is known as Net Primary Production (NPP).

Assuming an average efficiency of 50%, the NPP can be calculated as:

NPP = GPP x Efficiency

NPP = 10,000 joule x 0.5

NPP = 5,000 joule

Therefore, the energy available for primary producer level in the ecosystem is 5,000 joule.

Answer: Option D) 100 joule

Explanation:

The options provided in the question are not correct. The correct answer can be calculated as 1% of the incident solar energy, which is 10,000 joule. However, only 50% of this energy is available for primary producers after the deduction of respiration and other metabolic processes. Therefore, the energy available for primary producer level is 5,000 joule, which is equivalent to 0.5% of the incident solar energy. This is the final answer, which corresponds to option D.