Question

An orange roughy fish is a fourth-level consumer that requires almost ten times the amount of food available from the primary producers in the ecosystem. Why isn't more energy available from the primary producers?

A. Primary producers are not very efficient and lose most of their energy to the environment.
B. There is too much competition from other fourth-level consumers, leaving very little available to the orange roughy.
C. Only a fraction of energy is passed through each level, so there is less available to upper-level consumers.
D. The energy flow is unbalanced and tends to move toward the lower levels.

Answer 1

C is the correct answer. Remember the 10% rule that only 10% of the energy is passed from one trophic level to the next. Hope this helps!

Answer 2

The correct answer is option C

The fraction of energy that is available to the fourth level of the ecosystem is very less because the fraction of energy is passed on through each level.

According to the law, only 90% of the energy is transferred through each tropic level and rest of the energy is lost in the form of heat.

Thus, only a fraction of energy reaches the upper tropic level starting from the producers.