How does the washing of hands prevent a societal problem? it keeps water supplies clean. it treat inherited disease. it protect the environment. it reduces the spread of disease.

The Answer is D. It reduces the spread of disease/sickness.

We can rule A out since it has nothing to do with water pollution or keeping it clean. We can also rule out B since it can't treat diseases. Now we are left with C and D. C doesn't make sense since washing your hands isn't helping the environment, it is helping you. D makes sense since it helps people get sick and catch diseases that can be spread through viruses and germs which are located on the hands.

Hope I helped! ;)

answer: proteins

explanation: complement is   system of circulate in the blood in a inactive form

i believe is what you're looking for?