Match each disease with its correct type of vaccine:
| Column-I | Column-II | ||
| A. | Tuberculosis | 1. | Harmless virus |
| B. | Whooping cough | 2. | Inactivated toxin |
| C. | Diptheria | 3. | Killed bacteria |
| D. | Polio | 4. | Harmless bacteria |
| 1. | A-2 B-1 C-3 D-4 | 2. | A-3 B-2 C-4 D-1 |
| 3. | A-4 B-3 C-2 D-1 | 4. | A-1 B-2 C-4 D-3 |
The active form of Entamoeba histolytica feeds upon:
A high value of BOD (Biochemical Oxygen Demand) indicates that:
| 1. | water is pure |
| 2. | water is highly polluted |
| 3. | water is less polluted |
| 4. | consumption of organic matter in the water is higher by the microbes |
Most animals are tree dwellers in a:
The following graph depicts changes in two populations (A and B) of herbivores in a grassy field. A possible reason for these changes is that:

| 1. | both plant populations in this habitat decreased |
| 2. | population-B competed more successfully for food than population-A |
| 3. | population-A produced more offspring than population-B |
| 4. | population-A consumed the members of population-B |
Cryopreservation of gametes of threatened species in viable and fertile conditions can be referred to as:
| 1. | Advanced ex-situ conservation of biodiversity |
| 2. | In situ conservation by sacred groves |
| 3. | In situ cryo-conservation of biodiversity |
| 4. | In situ conservation of biodiversity |
Rachel Carson's famous book 'Silent Spring' is related to:
Which of the following is not one of the prime health risks associated with greater UV radiation through the atmosphere due to the depletion of the stratospheric zone?