I'm not sure if this is exactly correct, but to complete photosynthesis, plants need carbon dioxide and water. Usually sunlight as well. If you are supposed to be specific, you could put H2O. I hope I answered your question!
All of the above, hope this helps!
<span>Electron I think, but I might be wrong. </span>
Answer: Fishing, Overfishing is a huge problem depleting the amount of fish.
Explanation: swimming does no harm, agriculture is not in water and boating is not as big as a problem of fishing.
