Which of the following are purine bases?


Purine is a heterocyclic aromatic organic compound, consists of a pyrimidine ring fused to an imidazole ring.

Therefore, (i) and (ii) are the correct options.


Pyrimidine is also a heterocyclic aromatic compound. This contains two nitrogen atoms similar to benzene. Uracil and Thymine have the following structures.


Thus, (ii) and (iv) are incorrect options.

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