Question

what does cleaning water before we use it and after we use it require? very little energy pesticides very few chemicals chemicals and energy

Explanation:

Cleaning water before and after use generally requires chemicals for processes like disinfection and flocculation, and energy for pumping, filtration, etc. Pesticides are not related to water - cleaning processes. Using very little energy or very few chemicals is not accurate as water treatment often needs significant amounts of both.

Answer:

chemicals and energy