| I: | ‘memory’ of the immune system. |
| II: | ability to distinguish between self and non-self. |
| Statement I: | The primary and secondary immune responses are carried out with the help of two special types of lymphocytes, B-lymphocytes and T-lymphocytes respectively. |
| Statement II: | The T-cells themselves secrete antibodies, which help B cells to fight against pathogens. |
| 1. | Both Statement I and Statement II are correct. |
| 2. | Statement I is correct, but Statement II is incorrect. |
| 3. | Statement I is incorrect, but Statement II is correct. |
| 4. | Both Statement I and Statement II are incorrect. |