Can someone help pleaseee ?

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.

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?