15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.

A. Water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock

Explanation:

The aquifers are large natural reservoirs of water bellow the surface of the Earth. With all of the human activity, the aquifers have became badly damaged, especially when it comes to polluting them, thus making the water unusable. But not all pollution of the water in the aquifers comes from the human activities, as there are natural processes that pollute it and make it very dangerous. One way in which the water is getting polluted is by the chemical reactions between the water and the surrounding rocks. Some rocks have mercury and arsenic in them, and both of them are extremely toxic. If the rocks containing them are dissolved by the water, they will make the water very toxic, so anyone using it will probably end up dead.

a boiling water reactor does not boil the water. a pressurized water reactor boils the water faster. a pressurized water reactor is heated directly by the core. a pressurized water reactor does not use fission.

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