| Assertion (A): | Histamine is used to treat allergies. |
| Reason (R): | Histamine is a vasoconstrictor. |
| 1. | Both (A) and (R) are True and (R) correctly explains (A) |
| 2. | Both (A) and (R) are True but (R) does not correctly explain (A) |
| 3. | (A) is True, (R) is False |
| 4. | (A) is False, (R) is False |
| I: | ‘memory’ of the immune system. |
| II: | ability to distinguish between self and non-self. |