Final answer:
The average height of the troposphere in the middle latitudes is 8 kilometers (5 miles); it is the lowest layer of the Earth's atmosphere where most human activity and weather occurs.
Step-by-step explanation:
The average height of the troposphere in the middle latitudes is a) 8 kilometers (5 miles). The troposphere is the lowest layer of Earth's atmosphere, extending from the surface to about 11-13 km (7-8 miles) in altitude. As we go higher in the troposphere, both air density and temperature decrease.
The troposphere is where virtually all human activities occur and where most weather events originate.
The layer above the troposphere is the stratosphere, which continues from approximately 12 km to about 50 km above sea level. The transition between the troposphere and the stratosphere is known as the tropopause, which is the coldest part of the atmosphere. The troposphere is also the layer where Mt. Everest is located, which has a height of about 5.6 miles or 9 km.