Which terrain feature is characterized by a low area between hills?

A valley is defined as a low area between hills, often formed by the action of rivers or glaciers over time. This geographical feature typically has a distinct downward slope, leading to a lower elevation than the surrounding terrain. Valleys can vary significantly in size and shape, but they are primarily recognized by their surrounding elevated terrain—hills or mountains—which creates a natural basin or depression.

In comparison, a ridge is an extended length of high ground, which would not be a low area. A saddle refers to a dip or low point along a ridge, creating a sort of "hump" on either side but does not encompass a broader area like a valley. Similarly, a spur is a projection or a branch of a ridge that extends towards a valley or plain, generally elevated compared to the low areas around it. Therefore, the defining characteristic of a valley makes it the correct answer, distinguishing it from those other terrain features.