The correct option is 32 km from the earth’s surface.
Explanation
The atmosphere is a mixture of gases that surrounds the Earth, held in place by the planet's gravitational force. This gravitational pull causes the density of atmospheric gases to be highest near the surface and decrease rapidly with increasing altitude.
Detailed Analysis:
- The column of atmosphere is divided into five different layers depending upon the temperature condition. However, the mass distribution is determined by density and gravity.
- Because air is compressible, the weight of the overlying layers compresses the air below, making the lower atmosphere much denser than the upper atmosphere.
- 99 % of the total mass of the atmosphere is confined to a height of 32 km from the Earth's surface.
- Furthermore, approximately 90 % of the atmosphere's mass is found within just the first 16 km, and about 50 % is found below 5.6 km.
Key Takeaway:
The atmosphere is not uniform in density; it is densest at sea level. 99% of its total mass is concentrated within the first 32 km of altitude.