Q. Which of the following factors explain why the thickness of the atmosphere is maximum at the equator?

1. High insolation and strong convection currents occur in the troposphere over the Equator
2. Air is less dense at Equator
3. Equator exerts more gravitational pull on atmospheric gases
4. The centrifugal force due to Earth's rotation is maximum at Equator

Select the correct option from the codes given below:
Answer: Only 1, 2 & 4
Notes: Statements 1, 2, and 4 are correct. High insolation and strong convection (1) cause upward movement of air, less dense air at the equator (2) leads to atmospheric expansion, and maximum centrifugal force at the equator (4) reduces effective gravity. Statement 3 is incorrect, as gravitational pull is not greater at the equator but slightly less due to centrifugal force.