Question

a high altitude cloud that appears as a thin, sheet - like cover over the sky (common in the winter)
choose
a low altitude cloud that is dense, fluffy, and white with sharp outlines (rounded top and flat bottom).
choose
a low altitude cloud with ragged bases close to the horizon. dark grey, dense, typically blocking out the sky
choose

Explanation:

1. The first description matches cirrostratus clouds which are high - altitude clouds appearing as a thin, sheet - like cover.
2. The second description fits cumulus clouds which are low - altitude, dense, fluffy, white with sharp outlines, rounded tops and flat bottoms.
3. The third description is of stratus clouds which are low - altitude, have ragged bases close to the horizon, are dark grey and dense often blocking the sky.

Answer:

1. Cirrostratus
2. Cumulus
3. Stratus