Aforce can exist between two charged particles or objects even if they're as small as subatomic particles. between which of these would a repulsive force exist?
a. proton-proton
b. electron-electron
c. neutron-neutron
d. a and b

Which statement best describes the relationship between period and frequency of light waves? a) in wave b the period increases and the frequency decreases from wave a. b) in wave a the period increases and the frequency decreases from wave b. c) in wave b the period is shorter and the frequency is greater than in wave a. d) in wave a the period is shorter and the frequency is greater than in wave b.

Which property of a rock remains unchanged by mechanical weathering? a. total surface area b. size and shape c. mineral composition d. sharpness

Which answer tells the reason the earth’s climate is getting warmer? too many animals are becoming extinct. large glaciers are melting in antarctica. the earth is moving closer to the sun. driving cars gives off gases that trap heat in the atmosphere.