The _____ extends to a height of 18 km at the equator and 8 km at the poles.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Troposphere
The troposphere is the lowest layer of the atmosphere. Its average height is about 13 km; it is about 18 km thick at the equator, where strong heating carries air high by convection, and only about 8 km at the poles. Almost all weather, clouds and dust are found in this layer, and the temperature falls by about 1°C for every 165 m of height.