Which among the following make up the backbone of the DNA molecule?

Sugar and Phosphates .

The correct answer is Option (3)-Sugar and Phosphates .

The DNA molecule has a double-helix structure, and its backbone is formed by alternating sugar and phosphate molecules. The sugar in DNA is deoxyribose, and each deoxyribose molecule is linked to a phosphate group through a phosphodiester bond. This repeating pattern of sugar-phosphate forms the two long strands, or "rails," of the DNA ladder. The nitrogenous bases (adenine, thymine, cytosine, and guanine) are attached to the sugar molecules and project inward, forming the "rungs" of the ladder through hydrogen bonding.

The covalent bonds between the sugar and phosphate molecules provide stability to the DNA structure, while the hydrogen bonds between the nitrogenous bases allow for the complementary base pairing that ensures the accurate transmission of genetic information during processes like DNA replication. The sugar-phosphate backbone serves as a structural framework for the DNA molecule, providing support and maintaining the overall integrity of the genetic material.