The diagram shows a chemical reaction that occurs between hydrogen and oxygen. Which scientific law is BEST demonstrated by the reaction shown in the diagram? A. law of angular momentum B. law of universal gravitation C. law of conservation of mass D. law of conservation of energy

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.