Step 1: Understanding nucleic acids.
DNA and RNA are nucleic acids composed of sugars, nitrogenous bases, and phosphate groups.
Step 2: Identifying common components.
Both DNA and RNA contain the purine bases adenine and guanine.
Step 3: Analysis of options.
(A) Pentose sugar: Incorrect — DNA has deoxyribose, RNA has ribose.
(B) Purines: Correct — both contain adenine and guanine.
(C) Non-genetic: Incorrect — DNA is genetic material.
(D) Pyrimidines: Incorrect — DNA and RNA differ (thymine vs uracil).
Step 4: Conclusion.
The common characteristic between DNA and RNA is the presence of purines.