MCQ
Sickle cell-anaemia disorder arises due to
- ADuplication of a segment of $DNA$
- ✓Substitution in a single base of $DNA$
- CDeletion of a segment of $DNA$
- DDuplication in a base pair of $RNA$

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| Column $-I$ | Column $-II$ |
| $(A)$ Tuberculosis | $(i)$ Harmless virus |
| $(B)$ Whooping cough | $(ii)$ Inactivated toxin |
| $(C)$ Diphtheria | $(iii)$ Killed bacteria |
| $(D)$ Polio | $(iv)$ Harmless bacteria |