In the food chain given below, if the amount of energy available at fourth trophic level is 5 kJ, what was the energy available at the producer level?Grass → Grasshopper → Frog → Snake → Hawk(a) 500 kJ (b) 50 kJ (c) 5000 kJ (d) 5 kJ

Correct answer: (c) 5000 kJ 

Explanation: According to the 10 percent law, only 10 percent of the energy available in a trophic level is passed on to the next level. Hence, if the amount of energy available at the fourth trophic level is 5 kJ, the energy available at the producer level will be 5,000 kJ:

5 (4th Trophic Level) → 50  (3rd Trophic Level) → 500  (2nd Trophic Level) → 5,000 (1st Trophic Level or producers).