If a double-stranded DNA molecule is like a twisted rope ladder with handrails and steps, what would the steps in the ladder represent? A. phosphate groupsB. nitrogenous basesC. DNA polymeraseD. sugar (deoxyribose) molecules

The correct answer is B. nitrogenous bases

Explanation:

Double-stranded DNA is the genetic material in almost all the living organisms present on the earth. This DNA is present in a helical form. Each DNA strands us made up of nucleotides which are joined together by phosphodiester bond.

DNA is made up of two DNA strands therefore the two DNA strands are also joined and the two strands are joined together by hydrogen bond formation between two complementary nitrogenous bases.

These nitrogenous bases are adenine, guanine, cytosine, and thymine. Adenine and thymine are complementary to each other and guanine and cytosine are complementary to each other. Therefore the right answer is B.