The strands of the DNA double helix are held together by _______________________________________.

The strands of the DNA double helix are held together by hydrogen bonds. These hydrogen bonds form between the nitrogenous bases of the two strands: adenine (A) pairs with thymine (T), while cytosine (C) pairs with guanine (G). Each base pair is stabilized by two hydrogen bonds in the case of A-T pairs and three hydrogen bonds in the case of C-G pairs. This bonding is crucial as it maintains the structure of the DNA helix and ensures accurate replication and transmission of genetic information.

In addition to hydrogen bonds, the overall stability of the DNA structure is also influenced by base stacking interactions, which occur due to the alignment of the base pairs along the helical axis, allowing for hydrophobic interactions. Thus, both hydrogen bonding and base stacking contribute to the integrity and stability of the DNA double helix.