is a must oxygen to the humanbeings to survive on the earth?

Question

for the survival of humanbeing on the earth only oxygen is essential. or any thing is need to survive the humanbeings on the earth peacefully

Answer 1

Composition of Dry Air: % by volume

Nitrogen 78.08
Oxygen 20.95
Argon 0.95
Carbon dioxide 0.033
Neon 0.0018
Helium 0.00052
Methane 0.0002
Krypton 0.00011
Nitrogen oxide 0.00005
Hydrogen 0.00005

Yes. Humans must have oxygen to live. The human brain can go without oxygen for only about 4 minutes before it begins to die. The human heart pumps oxygen-rich blood throughout our bodies. When oxygen-rich blood is cut off from the heart, we have a "heart attack". Before we are born, we get oxygen from our mother's blood through the umbilical cord. Oxygen comes into our bodies through our lungs when we breathe. We breathe out carbon dioxide. Plants need carbon dioxide to live. They "breathe" out oxygen. We can get too much oxygen, as when we give concentrated oxygen to people in the hospital. The mix of oxygen that is safest is 21%. Babies who get too much oxygen can go blind. In Japan, there are Oxygen Bars where people can buy "extra" oxygen like a snack.

Answer 2

oxygen is a must, rest follow.

Answer 3

Oxygen is must.Or else you are dead