As an electromagnetic wave travels through space, it a) become stronger
b) keeps changing direction
c) loses energy to the medium
d) spreads out over a larger area

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 are acids or bases? 1. sodium hydrogen 2. barium hydroxide solution 3. carbonate solution

Is cutting your nails a physical or chemical change