Which of the following is true of dna? there are six nitrogenous bases involved. cytosine can pair with guanine and adenine. there are four nitrogenous bases involved. adenine always pairs with guanine. which of the following is not true of dna? question 3 options: hydrogen bonds hold nitrogenous bases together. guanine always pairs with cytosine. each nucleotide is connected to three nitrogenous bases. adenine always pairs with thymine. dna and rna are very similar; however, rna does not contain adenine and thymine. question 4 options: true false which of the following is considered the "zipper" and separates strands of dna during replication? question 5 options: helicase isomerase lipase polymerase