Answer:
It includes a series of elevations and depressions.
Step-by-step explanation:
Ridges are basically small elevations and if you look at them from a flat surface, they might even look like small mountains. In reality they are only 700ft tall.
Valleys on the other hand are plains with not ridges or small mountains.
Therefore a ridge and valley region would consist of a series of elevations due to ridges and depressions due to the plain valleys.