A boy found a solid metal box in his backyard. The box had been buried for so long, it was difficult to determine from what the box was made. The boy measured the box and found its volume (v) to be 17.63 cubic centimeters (cm3) and its mass (m) to be 158 grams (g). The boy knows the formula for density (D) is D = m/v. This table shows the density of several metals. DENSITY OF METALS * A. copper
B. gold
C. silver
D. tin

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.