Normally, the temperature decreases with the increase in height from the Earth's surface, because

Correct Option

Statement 1 is correct. The Earth's surface absorbs incoming solar radiation and subsequently re-emits it as longwave (infrared) radiation. This longwave radiation is the primary source of heating for the lower layers of the atmosphere. Heat is then transferred upwards through processes such as conduction and convection.

Statement 3 is correct. Atmospheric pressure and density decrease significantly with increasing altitude. At higher altitudes, there are fewer air molecules per unit volume. Consequently, there are fewer particles available to absorb and retain heat energy, leading to a decrease in temperature with height.

Incorrect Options

Statement 2 is incorrect. The concentration of moisture (water vapor) is highest in the lower troposphere, close to the Earth's surface, due to evaporation. Moisture content generally decreases rapidly with increasing altitude, with the upper atmosphere containing very little water vapor.

• Option (a) is incorrect because it excludes statement 3, which provides a valid reason for the temperature decrease with height.
• Option (b) is incorrect because statement 2 is factually inaccurate.
• Option (d) is incorrect because it includes statement 2, which is factually inaccurate.