Why does cloud formation become more likely when moist air rises along a mountain slope?

Correct answer: वायु ऊपर उठकर ठंडी होती है और संघनन होता है

Correct answer: A. When moist air is forced to rise along the windward side of a mountain, it enters regions of lower atmospheric pressure and expands. Expansion causes the rising air to cool. If it cools to its dew point, the water vapour becomes saturated and begins to condense into tiny droplets or ice crystals around small particles in the air. These droplets or crystals form clouds, often called orographic clouds because their formation is associated with relief or mountains. If the particles grow sufficiently, precipitation may also occur on the windward slope. Option A correctly gives the essential chain: mountain lifting, rising air, cooling, and condensation. Option B describes sinking and warming, which is not the process on the upslope side. Option C is wrong because a mountain does not destroy water vapour; it forces moist air upward. Option D is wrong because winds do not always stop at a mountain; they may be redirected or lifted. Cloud formation is more likely when the air is moist because more vapour is available for condensation. Memory cue: mountain lifting makes moist air rise, cool, and condense.