Assertion (A): The equatorial zone experiences low atmospheric pressure throughout the year despite having high surface temperatures. Reason (R): Intense solar heating causes warm air to expand, become buoyant, and rise vertically, leading to continuous upward mass transport and low surface air density.

💡 Solution & Explanation

Both the assertion and the reason are true, and the reason accurately explains the phenomenon. High insolation at the equator heats surface air, making it buoyant and forcing it to ascend through convection, which creates a continuous belt of low surface pressure known as the doldrums or Intertropical Convergence Zone. This vertical uplift drives the rising branch of the Hadley cell circulation. Equatorial low-pressure belts are responsible for heavy daily convective precipitation in tropical rainforests.