Carbonic acid (H2CO3)does not dissortate 100 percent in water. What type of substance is it ?
weak acid
Strong base
strong acid
weak base

a small container that holds a source of energy a solar cell that captures light energy and converts it into electricity a voltaic cell that uses the oxidation of a fuel to produce electricity

explanation:

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

it is b that is the answer.