Question

For human survival, approximately what percentage of air must be oxygen?

Answer 1

20.9 around 78 percent nitrogen only 20.9 for oxygen

Answer 2

20.9 percent

Around 78% of the air is nitrogen gas, and only 20.9% is oxygen.

Step-by-step explanation:

20.9 percent

Around 78% of the air is nitrogen gas, and only 20.9% is oxygen.

Hope this helps.