Question

the region of washington state that has many mountains, including active volcanoes such as mt. rainier and mt. st. helens
regions shown: columbia basin, cascade mountains, western lowlands, coastal region

Explanation:

The text is about the Cascade Mountains region of Washington State, which has active volcanoes like Mt. Rainier and Mt. St. Helens. The Cascade Mountains are a mountain range in the Pacific Northwest with volcanic activity, so the region described is the Cascade Mountains.

Answer:

Cascade Mountains