The correct sequence of different layers of the atmosphere from the surface of the Earth upwards is:

Answer: (c) Troposphere, Stratosphere, Mesosphere, Ionosphere

Troposphere → stratosphere → mesosphere → ionosphere (thermosphere).

The idea

The main atmospheric layers are ordered by how temperature changes with height. The weather layer is lowest, followed by the ozone-heated layer and then the colder mesosphere. The ionosphere is a region of charged particles rather than a separate temperature layer. School diagrams commonly place its main part with the thermosphere above the mesosphere.

Why the others are wrong

(a) Puts the ionosphere below the mesosphere.

(b) Starts with the stratosphere.

(d) Starts with the stratosphere.

Elimination technique

The surface weather layer must come first, removing (b) and (d). Of the remaining codes, (c) places the mesosphere below the main ionospheric region, matching the conventional school sequence.

Also know

The exosphere is the very tenuous outer region beyond the thermosphere. The ionosphere begins within the upper mesosphere and extends through much of the thermosphere, so the two classifications overlap. Tropopause, stratopause and mesopause are boundaries, not full layers. Radio propagation depends on ionisation, while weather depends mainly on lower-air moisture and movement.