Why is groundwater usually less polluted than surface water?

In a scientific experiment, a is any factor that can be changed or be changed

Astate's representation in the u.s. senate is based on a) equal representation. b) the state's population. c) the state's electoral votes. d) the size of their major cities.this independent regulatory agency was created in 1974 to oversee and regulate the financing of political campaigns in the united states. a) warren cthis independent regulatory agency was created in 1974 to oversee and regulate the financing of political campaigns in the united states. a) warren commission (wc) b) federal election commission (fec) c) equal opportunity commission (eoc) d) securities and exchange commission (sec)

Mengapakah wujudnya perbezaan tanggapan terhadap sumber?