Plz help asap

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Between 2014 and 2016, more than 25,000 children in flint, michigan, drank water that was contaminated with lead from lead pipes. during this time, the city claimed the water was safe to drink. which of these actions could the city have taken to ensure that the drinking water was free from lead?

Enzymes affect the reactions in living cells by changing the