what is the structure of the dna molecule?\na single helix\nb double helix\nc alpha helix

Answer

Brief Explanations:

DNA is composed of two strands that wind around each other, forming a double helix structure. This was discovered by Watson and Crick. A single helix is not the structure of DNA. The alpha - helix is a common secondary structure in proteins, not in DNA.

Answer:

B. Double helix