The ultimate source of energy (for most ecosystems) is the sun<span>. The ultimate fate of energy in ecosystems is for it to be lost as heat. Energy and nutrients are passed from organism to organism through the food chain as one organism eats another.</span>
Answer:
So this is just a guess but i think its D but like I said its a guess.
The answer your looking for is 20 Amino Acids.<span>
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Since chloroplast use energy to make food for plant cells (Photosynthesis) I could compare it to lunch money, and how you have to keep refilling up, and up, just to use it again for food, for yourself.