Consider the following food chain : Grass → Grasshopper → Frog → Snake → Eagle If the amount of energy availa…

Question

Consider the following food chain :
Grass → Grasshopper → Frog → Snake → Eagle
If the amount of energy available at third trophic level is 50 kJ, the available energy at the producer level was :

Accepted Answer

## Model Answer **(D) 5000 kJ** Using the 10% law: Third trophic level (Frog) = 50 kJ → Second trophic level = 500 kJ → First trophic level (Grass/Producer) = **5000 kJ**. ## Explanation At each trophic level, only 10% of energy passes to the next level. So to find the energy at a lower level, multiply by 10. Third trophic level = 50 kJ, so second = 50 × 10 = 500 kJ, and producer level = 500 × 10 = 5000 kJ. Remember: Frog is at the **third** trophic level (Grass→1st, Grasshopper→2nd, Frog→3rd).

Science — CBSE Class 10 board question