Q: You are presented with the quiz "the basic necessity of an ecosystem enters in the form of what?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "energy enters ecosystems in the form of sunlight or chemical compounds" and "energy is a basic necessity of an ecosystem". So, what's the best answer to the question?

Choose your answer from:
i. heat
ii. recycling
iii. trees
iv. food
v. sunlight
vi. adding heat
vii. movement
viii. root growth
A:
v.