Final answer:
The most important process of cloud formation in the atmosphere is condensation. Rising air currents carry water vapor into the atmosphere, where it cools and condenses into tiny droplets of liquid water that form clouds and eventually fall as precipitation.
Step-by-step explanation:
The most important process of cloud formation in the atmosphere is condensation. As rising air currents carry water vapor into the atmosphere, the water vapor cools and condenses, changing from a gas to tiny droplets of liquid water. These water droplets may then form clouds and if they become big enough, they fall as precipitation in the form of rain, snow, sleet, hail, or freezing rain.