Which of the following best defines precipitation?

The correct definition of precipitation is best captured by stating that it refers to any form of water falling from the atmosphere to Earth. This encompasses a variety of phenomena, including rain, sleet, snow, and hail, all of which are important for the Earth's water cycle. Precipitation occurs when atmospheric water vapor condenses into droplets or ice crystals that become too heavy to remain airborne, resulting in a fall to the ground.

Water vapor in the atmosphere, while a component of the weather system, does not define precipitation itself, as it involves the vapor state rather than liquid or solid falling to the surface. A specific threshold of rainfall, such as exceeding 2 inches, is too narrow to define precipitation, as it excludes other forms and amounts of precipitation that are also significant. Additionally, fog or mist is classified as a weather phenomenon involving suspended water droplets in the air but does not constitute precipitation, as it does not involve falling water. Therefore, option B accurately captures the broad nature of precipitation in meteorological terms.