Question

which hold water until it is needed?
○ dams
○ reservoirs
○ aqueducts
○ valleys

Explanation:

Dams are structures that block water flow to store it, while reservoirs are the artificial lakes created by dams that hold water for later use. Aqueducts transport water, and valleys are natural landforms that do not intentionally hold water for use. Both dams and reservoirs function to hold water until needed.

Answer:

A. dams
B. reservoirs