Question

the 10% rule of ecosystems says that only 10% of the energy is passed on to the next trophic level. what happens to the rest of the energy? it gets released into the environment as heat. it goes back into plants. we dont know what happens to it.

Explanation:

In ecosystems, during energy transfer between trophic levels, most of the energy (90% of what's not passed to the next level) is used by organisms for metabolic processes like respiration, and this energy is released into the environment as heat. The option "It goes back into plants" is incorrect as energy flow in ecosystems is unidirectional (from producers to higher trophic levels, not back to plants in this context). The option "We don't know what happens to it" is also incorrect as the fate of this energy (release as heat) is well - understood.

Answer:

A. It gets released into the environment as heat.