Correct Option
The correct option is 2 and 3 only.
Explanation
The capacity of air to hold water vapour refers to the maximum amount of moisture the air can retain at a specific condition, known as the saturation point. This capacity is governed by the thermal energy of the air molecules.
Statement-wise Analysis
- Statement 1 is Incorrect: The moisture-holding capacity of air is not independent of temperature; rather, it is strongly dependent on it.
- Statement 2 is Correct: There is a direct positive relationship between air temperature and its moisture-holding capacity. As the temperature of the air increases, its capacity to hold water vapour increases. Conversely, as air cools, its capacity decreases, potentially leading to condensation.
- Statement 3 is Correct: In the context of general atmospheric geography, the potential capacity of air to hold water vapour is considered to be determined entirely (or solely) by its temperature. While other factors like pressure have minor theoretical roles in specific physics contexts, for geographical purposes, temperature is the defining variable for saturation vapour pressure.
Key Takeaway
Temperature is the primary determinant of the atmosphere's capacity to hold moisture; warmer air can hold significantly more water vapour than cold air.