Which of the following clouds is classified as a high-level cloud?

The classification of clouds is largely based on their height above the Earth's surface. High-level clouds are typically found at altitudes above 20,000 feet (6,000 meters) and are composed primarily of ice crystals due to the low temperatures at those heights.

Cirrostratus clouds fit this definition perfectly, as they are indeed high-level clouds. They are thin, ice-crystal clouds that often cover the sky and can give it a milky appearance. These clouds are known for their role in creating halos around the sun or moon, a phenomenon resulting from the refraction of light through the ice crystals within the cirrostratus.

The other types of clouds mentioned—stratus, altostratus, and cumulus—are classified as lower or mid-level clouds. Stratus clouds are low, uniform clouds typically found below 6,500 feet (2,000 meters). Altostratus clouds sit at mid-level altitudes, between about 6,500 to 20,000 feet, and are characterized by a gray or blue-gray hue, often covering the entire sky but allowing some light to filter through. Cumulus clouds are generally associated with vertical development and can indicate fair weather, but they are also typically found at lower alt