Answer:
I think the answer would be D,I'm not really sure though,hope I'm right,sorry if I,m not :)
Explanation:
Heat is then the by-product of the light energy from the Sun flowing through the biosphere. Organisms are inevitably dependent on sunlight to perform essential biological processes in order to sustain life. In the absence of this energy, all the organisms on Earth would die.
The answer is, D. Organ system
