6. Imagine you are riding a bike, and you hit a large rock in your path. The rock puts external force on your bike. Which of the following is likely to
happen according to Newton's First Law of Motion?
A. Your bike stops moving forward
B. Your body flies forward.
C. The rock may move backward
D. All of the above

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.