Answer:
oxygen(O2), Nitrogen(N2) ,water (H2O),Carbon dioxide (CO2)
This is actually incorrect, the distance as stated above either from trough to trough or from crest to crest within a corresponding wave, would be referred or called as the wavelength of the given wave.
Variable B will become lower due to variable A becoming smaller think of it like a seesaw if you put something on one side there will be a reaction on the other =)