All bacteria is harmful?

True
False

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.

What is the measured amount of a product obtained from a chemical reaction?

Silver reacts with oxygen to produce silver oxide. (write balanced chemical equation and identify type of chemical reaction.)