Question

a model of dna is shown.which label identifies a hydrogen bond?a. structure 1b. structure 2c. structure 3d. structure 4

Explanation:

• In a DNA model, hydrogen bonds are the weak bonds that hold the two strands of the double helix together.
• Structure 4 is the one that represents the hydrogen bond as it is the connection between the nitrogenous bases (the "rungs" of the DNA ladder). Structure 1 and 3 are parts of the sugar - phosphate backbone (the "sides" of the DNA ladder), and Structure 2 is not a hydrogen bond.

Answer:

D. Structure 4