Answer: 21%
Explanation:
The atmosphere is the gaseous portion of the planet Earth. It therefore consists of several gases and air particles.
In the atmosphere,
-Nitrogen is the most abundant gas with 78%
- Oxygen takes 21%,
- Carbon dioxide takes 0.03%,
- the remainder is unreactive gases and particles.
Answer:
The amount of oxygen in earths atmosphere was about one ten-quadrillionth of the of the amount presented today
