Question

Which of the following is a common source of groundwater pollution?

Oil dumping and oil spills

Tossing candy bar wrappers into a stream

Flushing household chemicals down the toilet

Leaking storage containers outside factories

Answer 1

I assume that whoever posed this problem wants you to recognize the distinction between groundwater pollution and surface-water pollution. Otherwise, I do not see why the answer would not be "all of the above." But you really ought to post your question under the Physics or Chemistry forums instead, as this has little to do with computers.