Question

dna basics
in dna, the phosphate and sugar molecules form the
__________ of two strands. the strands are
joined together by __________ bonds that connect
ucleotides. adenine always bonds to __________
and cytosine always bonds to __________. the whole
molecule is coiled like a twisted ladder, or
double helix

Explanation:

DNA has a double - helix structure. The phosphate and sugar form the backbone. Hydrogen bonds link the two strands. Adenine pairs with thymine (A - T) and cytosine pairs with guanine (C - G) due to complementary base - pairing rules.

Answer:

backbones, hydrogen, thymine, guanine