Answer:
b. troposphere.
Explanation:
The troposphere is the lowest layer of the earth's atmosphere, being the region in which we live and where meteorological phenomena occur.
Its height varies with the point away from the surface. At the poles, for example, it reaches 7 km altitude and 16 km in the Ecuador region.
It is in the troposphere that rain, lightning, clouds and air pollution occur.
The meaning of troposphere comes from the Greek "tropos" and means change.
The chemical composition of the troposphere is as follows:
Oxygen - 21%
Argon - 0.9%
Water vapor - 0.4%
Carbon Dioxide - 0.04%
The troposphere concentrates most of the water vapor from Earth's atmosphere. The amount of vapor results from the process of evaporation and transpiration of the earth's surface.