Answer:- 4,000 kilo-calories.
Step-to-step-explanation:-
We know that the ten percent rule says that when energy is passed in an ecosystem from one tropic level to the next then only ten percent of the energy will be passed on.
Given: The total amount of energy in the producer level ecosystem = 40,000 kilo-calories.
Then, the amount of energy in the first level = [10% of 40,000] kilo-calories.
⇒ The amount of energy in the first level =
kilo-calories.
⇒ The amount of energy in the first level = 4,000 kilo-calories.