Final answer:
The bases in a DNA strand are connected by hydrogen bonds, which form between the complementary pairs: adenine with thymine and guanine with cytosine. These essential bonds allow DNA to maintain its unique double helix structure.
Step-by-step explanation:
How do each of the bases stay connected in a DNA strand? In a DNA double helix, the bases are connected by hydrogen bonds. These bonds occur between the nitrogenous bases adenine, thymine, guanine, and cytosine that make up the complementary base pairs within the double helix structure. Adenine pairs with thymine through two hydrogen bonds, and guanine pairs with cytosine through three hydrogen bonds. Thus, the correct answer is B) Hydrogen bonds.
Hydrogen bonds and Van der Waals interactions are the types of weak associations that enable the structure and function of DNA molecules. While hydrogen bonds stabilize the pairing of bases, phosphodiester bonds form the sugar-phosphate backbone, which plays a different role in connecting the DNA strands together. The pairing of bases, crucial for DNA's structure and function, occurs at the interior of the double helix.