MCQ
Purines possess nitrogen at which position?
- A1, 2, 4 and 6 position
- B1, 3, 5 and 7 position
- C1, 3, 7 and 9 position
- D1, 2, 6 and 8 position
Explanation:
Purines consist of a six-membered and a five-membered nitrogen containing ring, fused together. It possesses nitrogen at 1,3,7 and 9th position.

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| Column - $I$ | Column - $II$ |
| $(a)$ Pleiotropic gene | $(i)$ Both allele express equally |
| $(b)$ Co-dominance | $(ii)$ Change in nucleotide |
| $(c)$ Epistasis | $(iii)$ One gene shows multiple phenotypic expression |
| $(d)$ Mutation | $(iv)$ Rust disease |