Because all compounds are neutral, the total charges on the cations and anions must add up to a. one b. two c. zero

Zero. cations have positive charge while anions have negative charge.
eg. Mg2+ + 2Cl- -> MgCl2

They are all full and don't need any more electrons in there outer shell.

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .