The descent of masses of snow from their original positions sometimes happens suddenly in avalanches, but it is usually very gradual in the form of glaciers. Also, snow exposed to warmer air ultimately melts and flows away as water.

Question

Which of the following sentences most likely precedes this excerpt?

Some of these natural occurrences reduce the amount of snow on the mountainside.
Some snow always stays on the mountainside.
Once snow slopes become too steep, the lower layers can no longer remain on the mountainside.
Each time it snows, more snow accumulates on the mountainside.

Answer 1

The sentence that most likely precedes the excerpt is:

Some of these natural occurrences reduce the amount of snow on the mountainside.

This sentence sets the context for the following discussion about avalanches, glaciers, and the melting of snow, indicating that the following information will elaborate on how snow can be removed from or decrease in quantity on the mountainside.