Please help me I will give you the brain thing with extra points if you help me, please. I need to get this right. 4/10

The number of neutrons is equal to the atomic number minus the atomic mass. a. true b. 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.

Which of the following is a physical property flammability heat of combustion solubility and toxicity