Answer:
Heat
Explanation:
in an ecosystem there are multiple types of lifeforms, this seems to be asking about those.
First plants take light energy and convert it into gluecose, a stored form of chemical energy in the plant. Said plant will use energy to grow ans will break down the glucose to respire, producing heat.
Additionally, buclear energy is weong becasue living things are not nuclear plants and water isnt a form of enrgy by it self so the answer may be refering to hydroelectric energy which is also wrong
