Which step in cloud formation involves the collection of water vapor?

• A. Air expands
• B. Air decreases temperature
• C. Air becomes saturated
• D. Water droplets begin to form

Answer: (C)

The process of cloud formation involves several key steps, and the collection of water vapor is critical among those steps. When air is heated, it can hold more moisture in the form of water vapor. As air rises, it expands and cools, and the capacity of the air to hold water vapor decreases.

When air becomes saturated, it means that it has reached its maximum capacity for holding moisture. At this point, any additional water vapor cannot remain in the gas phase and begins to condense into tiny water droplets, which eventually leads to cloud formation. Therefore, the step indicating that air becomes saturated is the correct choice, as it directly relates to the accumulation of water vapor that leads to the transition from vapor to liquid droplets, marking a crucial phase in the overall cloud formation process.