| Assertion A: | An antibody is a protein molecules made by the lymphocytes. |
| Reason R: | An antibody binds to a specific foreign antigen and neutralizes its odd effects. |
| 1. | Both A and R are true and R is the correct explanation of A |
| 2. | Both A and R are true but R is NOT the correct explanation of A |
| 3. | A is true but R is false |
| 4. | A is false but R is true |
| I: | Salmonella typhi is a pathogenic bacterium which causes typhoid fever in human beings. |
| II: | These pathogens generally enter the small intestine through food and water contaminated with them |
| III: | The pathogen remains confined to the small intestine. |
| IV: | Intestinal perforation and death may occur in severe cases. |
| V: | Typhoid fever could be confirmed by Widal test. |
| 1. | Streptococcus pneumoniae and Staphylococcus aureus |
| 2. | Haemophilus influenzae and Streptococcus pneumoniae |
| 3. | Pneumocystis carinii and Mycoplasma hominis |
| 4. | Streptococcus pyogenes and Bacillus anthracis |