Question

describing mountains
fill in the blanks to complete each statement about mountains.
several mountains together form a mountain
a few of these combined form a mountain system. several
systems combined form a mountain
which can stretch thousands of miles in length.

Explanation:

To solve this, we recall the hierarchical structure of mountains. Several individual mountains form a mountain range. Then, multiple mountain ranges combine to form a mountain system. Finally, multiple mountain systems combine to form a mountain belt (or mountain chain, but "belt" is more accurate here as it refers to a large, elongated group of mountain systems).

Answer:

First blank: range
Second blank: belt