What type of bond holds the two strands of DNA together?

The two strands of DNA are held together primarily by hydrogen bonds, which form between the nitrogenous bases of the nucleotides. Each base pairs with a complementary base on the opposing strand (adenine pairs with thymine, and cytosine pairs with guanine) through these hydrogen bonds. This arrangement contributes to the double helix structure of DNA, allowing it to maintain stability while also being flexible enough to allow for the unwinding necessary for processes like replication and transcription.

While covalent bonds do play a crucial role in the overall structure of DNA, they are responsible for linking the sugar and phosphate components of the backbone within each strand, rather than connecting the strands to each other. Ionic and peptide bonds are not involved in the structure of DNA; ionic bonds usually occur in salt compounds and peptide bonds form between amino acids in proteins. Thus, hydrogen bonds are the key to holding the two complementary strands of the DNA double helix together.