Answer:
20 units of energy
Explanation:
Given that the ecological efficiency of the ecosystem is 10%, (meaning as energy is transferred from one trophic level to another, 90% of energy is being lost), units of energy the human received of the original 2000 units can be calculated as follows:
Energy received by grass = 2000 units
Energy transferred to cow = 10% of 2000 units = 10/100 × 2000 units = 200 units (1800 units is lost)
Energy transferred from cow to the human = 10% of 200 units = 10/100 × 200 = 20 units (180 units lost)
Only 20 units of the original 2000 units is received by the human.
