Which of the following are examples of purines, the building blocks of DNA and RNA?

✅Explanation:
Purines are nitrogenous bases that, along with pyrimidines, form the building blocks of nucleic acids like DNA and RNA. Adenine (A) and Guanine (G) are the two main purines found in DNA and RNA.

📌Other Options Explanation:
Deoxyribose and ribose are sugars that make up part of the backbone of nucleic acids.
Cytosine and uracil are pyrimidines, another type of nitrogenous base in nucleic acids.
Colchicine and X-rays can affect cell division or cause mutations.