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
Answer:
convex lens
Explanation:
because when parallel rays of light pass through a lens are brought together through a lens
Answer:
protons is 7 neutrons should be 9
Explanation:
protons number is its atomic number
the number of protons and the number of neutrons determine an element's mass number.