Answer:
D. About ten percent of the energy at one trophic level is passed to the next trophic level
Explanation:
In an ecosystem, the amount of energy decreases at each trophic level. Precisely, the energy transfer from lower trophic level ot high trophic level is calculate to be 10% of the previous level. Rest of the energy is just wasted through metabolic activities (e.g. heat). For example, if a grassland ecosystem has total energy of 10,000 Kcal, only 1000 Kcal would be transferred to the primary consumers, and then 100 Kcal to secondary consumers, and finally 10 Kcal to tertiary consumers. See figure for better understanding.
First option is incorrect because energy flow in an ecosystem is unidirectional. Option B and C are incorrect because energy flow is not dependent on specific animal/plant species but rather at trophic levels.
