There are a lot of reasons why gum is bad for you but a main reason because if you make a bubble and swallow it you could choke. Another reason is because it breaks down your gums.
Answer: 1/R = 1/R1 + 1/R2+ ...+ 1/Rn
R is resistance of system in which there are resistors R1, R2 , ... Rn parallel.
C. ultraviolet rays & D. gamma rays
