Rainforests are a feature of
the Columbia Basin.
the Olympic Mountains.
O the Puget Lowlands.
O the Willapa Hills.

Answer:

Rainforests are a feature of the Olympic Mountains.

Explanation:

The rainforests are something that is associated with the tropical regions around the Equator. This should not come as a surprise as the vast majority of them are found in this part of the world, but very often it is forgotten that there are other rainforests, outside of the tropics. These rainforests have all very similar characteristics to the tropical rainforests but they are located in the temperate regions in the mid-latitudes.

One such rainforest is found near the northwestern coast of the United States, in the state of Washington, on the Olympic Mountains. These mountains are located just above the coastline, and because they act as a barrier, the constant humidity that comes from the ocean is built up and there is rainfall throughout all of the year. Because there is rain all year round, there is lush vegetation, though it has to be noticed that the amount of plant species is relatively low compared to the tropical rainforests. The animal species tend to be in a higher number than in most of the other biomes in the temperate climates but again much smaller than in the tropical rainforests.