Which type of precipitation forms when ice crystals fall through a cloud of supercooled water droplets?

The correct response is snow, which forms when ice crystals, also known as snowflakes, fall through clouds that contain supercooled water droplets. Supercooled water droplets are liquid water that exists below freezing temperatures without turning into ice. As the ice crystals descend through the cloud, they collide with these supercooled droplets, which freeze onto the crystals and help them grow. Eventually, the crystals become heavy enough to fall to the ground as snow.

This process is distinct from the formation of rain or sleet. Rain typically occurs when warm air causes ice crystals or snowflakes to melt before reaching the ground, resulting in liquid precipitation. Sleet, on the other hand, forms when snowflakes or ice crystals fall through a warm layer of air, melt partially into rain, and then refreeze into small ice pellets before reaching the earth. Water vapor is a gaseous form of water and does not refer to any precipitation type. Therefore, understanding the conditions under which snow forms clarifies why it is the correct answer in this context.