Question

which of the following statements about dna is correct?
dna contains uracil as one of its nitrogenous bases.
dna is made up of amino acids as its monomer.
dna is a double helix molecule.
the phosphate group in dna connects the nitrogen bases.

Explanation:

• Analyze each option:
• Option 1: DNA has thymine, RNA has uracil. So this is incorrect.
• Option 2: DNA's monomer is nucleotide, amino acids are for proteins. Incorrect.
• Option 3: DNA is a double - helix molecule. This is a well - known fact about DNA structure.
• Option 4: In DNA, the phosphate group connects to the sugar (deoxyribose), not the nitrogen bases. Incorrect.

Answer:

The option "DNA is a double helix molecule." (the third option in the list of statements about DNA)