What are changes in an ecosystem due to natural and human activity?

Which statements about wells are true? check all that apply. a) wells bring groundwater from the unsaturated zone to the surface of the water. b) wells need to be drilled below the water table. c) if water is pumped from a well too quicky, the well may run dry. d) water from wells is generally not safe to drink. e) water gushes from artesian wells due to pressure.