Answer:
Gas!
Explanation:
It can be conserved by keeping it underground, even though it's dangerous if you keep it underground too far down it can explode and cause the Earth to have an huge expplosiion or Earthquake to where the earth can shift it's tectonic plates and cause new areas to be moved, or gone. To deplete this gas, they use it in cars, stoves, etc. and they use it up to where there can be no more gas left. Even though there is still natural gas under the Earth''s surface it can still be found and depleted in different type of unique ways people discover.
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