Answer:
You may be referring to the gas that makes up 21% of the earth's atmosphere, which is oxygen.
Explanation:
According to NASA, the gases in Earth's atmosphere include:
Nitrogen — 78 percent
Oxygen — 21 percent
Argon — 0.93 percent
Carbon dioxide — 0.04 percent
(Trace amounts of neon, helium, methane, krypton and hydrogen, as well as water vapor)
We could reduce soil erosion and recycle phosphorus from farm and human waste so that we could help make food production sustainable and prevent algae blooms. We can also do land reclamation as well to help solve this problem. With the land, we would have to design a system to where the land could be functional again in order to plant crops, trees, also to help the wildlife that was once a part of the island. Therefore if the design is done before the mining then afterward we can do the reclamation of the land which would help the people to be able to function after the mining. It would also help the future generations that come along after the previous generations. Everyone must work together in the process in order for everyone to survive. If all this is done then the people of the island would not have to import their food. The reclamation process is the most important thing that has to be designed first whether it is land, soil, water, lakes, and clay then after plant trees, vegetation, and other forms of plants to help replenish the land after the mining is done.
I hope I helped :3
