Answer the following question given this paragraph: 

Two DNA strands link together in an antiparallel direction and are twisted to form a double helix. The nitrogenous bases face the inside of the helix. Guanine is always opposite cytosine, and adenine is always opposite thymine.


Q: What is formed when two dna strands link together in an antiparallel direction and are twisted?

 Choices:

- guanine

- anti-helix

- RNA

- double helix

A:
double helix
