Question

select the true statements.
all four dna nucleotides have identical 5-carbon sugars.
all four dna nucleotides have identical phosphate groups.
all four dna nucleotides have identical nitrogenous bases.

Explanation:

1. For the statement "All four DNA nucleotides have identical 5 - carbon sugars": DNA nucleotides contain deoxyribose as the 5 - carbon sugar, and all four (adenine, thymine, cytosine, guanine - containing) nucleotides have deoxyribose, so this is true.
2. For the statement "All four DNA nucleotides have identical phosphate groups": Each DNA nucleotide has a phosphate group with the same structure ($PO_4^{3 - }$ - related in the nucleotide), so this is true.
3. For the statement "All four DNA nucleotides have identical nitrogenous bases": The four DNA nucleotides have different nitrogenous bases (adenine, thymine, cytosine, guanine), so this is false.

Answer:

A. All four DNA nucleotides have identical 5 - carbon sugars (True)
B. All four DNA nucleotides have identical phosphate groups (True)
C. All four DNA nucleotides have identical nitrogenous bases (False)

The true statements are: "All four DNA nucleotides have identical 5 - carbon sugars" and "All four DNA nucleotides have identical phosphate groups"