Salutations!
<span>Cells that perform similar functions combine to form: ----
</span><span>Cells that perform similar functions combine to form: tissues. A group of tissues working together combine to form an organ system. Organs working together combine to form an organ system. Organ system performing their functions makes an organism.
Thus, your answer is option D.
Hope I helped (:
Have a great day!</span>
Answer:
Energy that is not used in an ecosystem is eventually lost as heat. Energy and nutrients are passed around through the food chain, when one organism eats another organism. In each case, energy is passed on from one trophic level to the next trophic level and each time some energy is lost as heat into the environment.
Explanation:
