Depends on what mountain you are on
If you are on Everest, then the amount of effective oxygen available would be 6.9% (0 altitude would be 20.9)
that is why anyone should always bring oxygen tanks when climbing a high mountain
Explanation:
for 1 it has to be false cause cutting tree ain't good.
for 2 I'm not sure, maybe it's TRUE..
Mitpchondria, I hope I helped,Can I have brainliest!
