The smallest of the -2 ions?

Different isotopes indicate that an element will have different numbers of

If a solution is considered basic, then a) the hydroxide ion and hydronium ion concentrations are equal. b) the hydroxide ion concentration is less than the hydronium ion concentration. c) the hydronium ion concentration is greater than the hydroxide ion concentration. d) the hydroxide ion concentration is greater than the hydronium ion concentration.

If an area has high air pressure and low humidity, what type of weather will it most likely have? plz !