What happens to the overall pressure in the troposphere as altitude increases?

• A. Increases steadily
• B. Remains constant
• C. Decreases sharply
• D. Decreases gradually

Answer: (C)

As altitude increases in the troposphere, the overall pressure decreases. This decrease in pressure with altitude occurs due to the thinning of the air, which means that there are fewer air molecules above a given point exerting force. The troposphere contains about 75% of the atmosphere's mass, and as you ascend, the weight of the air above decreases, leading to lower pressure.

While some might argue that pressure could remain constant, this is not the case in the troposphere. The idea of it increasing steadily or remaining constant does not align with the physical principles of atmospheric pressure. In addition, a sharp decrease implies a more abrupt change, which does not accurately reflect the gradual, smooth decrease of pressure typically observed with altitude in the troposphere.

Therefore, the correct understanding is that as altitude increases, pressure decreases gradually, reflecting the gradual reduction in air density and the amount of air that is above any given level in the troposphere.