Which of the following correctly completes the following equation:
nitrogenous base + sugar + phosphate group = ?
nucleotide
amino acid
enzyme
antibody

I am pretty sure that  the following which correctly completes the following equation is : Nitrogenous base + sugar + phosphate group = Nucleoside. Just according to the main poins of its definition you can easily assure yorself it is correct, as Nucleotide is an organic compound which is made from of nitrogenous base, a sugar, and a phosphate group. 
Do hope it will help you! Regards.

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 .