Assertion (A): The thickness of the atmosphere is maximum over the Equator. Reason (R): High insolation and strong convection currents occur over the Equator.

Assertion (A) is true. The troposphere, the lowest and densest layer of the atmosphere where most weather occurs, is indeed thickest over the Equator (around 16-18 km) and thinnest over the poles (around 8-9 km). Reason (R) is true. The Equator receives maximum direct solar radiation (insolation) throughout the year, leading to significant heating of the surface and the air above it. This warm air becomes less dense and rises, creating strong convection currents. Reason (R) is the correct explanation for Assertion (A). The high insolation at the Equator causes the air to heat up considerably. This heated air expands and rises due to strong convection. This thermal expansion and upward movement of air push the tropopause (the boundary between the troposphere and stratosphere) to a greater height, making the atmospheric column, particularly the troposphere, thicker over the Equator compared to the colder, denser air at the poles.