When Prophet's ( peace be upon him) illness worsened he asked his wives permission to be nursed by

Explanation:

I'm guessing he requested either servants, that he was close to. OR, having affairs with, concubine...

Underground water like in a well can't clean itself because of man made pollutants, from large farms that seep through the ground. there is little agitation to keep it areated, and becomes stagnant, which develops bacteria and other pathogens to make us sick..