Question

A Bluefin tuna eats a sardine that has recently been feeding on plankton. The sardine has 1,000 joules worth of energy, but the tuna ultimately gains only about 100 joules. Where does the rest of the energy go?

A. It is destroyed and cannot be recovered.

B. It is used for cell functions or transformed to heat energy.

C. It was used by the sardine as it tried to get away from the tuna.

D. It reverts back to the plankton that the sardine ate.

Answer 1

The answer is B.
There is a general rule that only around 10% of the energy in an organism is transferred to the next trophic level. 

Answer 2

Answer:

The correct answer would be B. It is used for cell functions or transformed to heat energy.

It can be explained with the help of ten percent law which states that only ten percent of the energy available at a particular trophic level is transferred to the higher trophic level.

The rest or maximum of the energy is lost as heat as a result of cellular respiration.

It is why the tuna only gets 100 joules (ten percent of 1000) of energy from sardine.