| 1. | A population | 2. | A species | 
| 3. | A biological community | 4. | An ecosystem | 
| Statement I: | Entire biosphere is regarded as a global ecosystem by many ecologists. | 
| Statement II: | The global ecosystem is divided into terrestrial and aquatic ecosystem for convenience. | 
| 1. | Only Statement I is correct. | 
| 2. | Only Statement II is correct. | 
| 3. | Both Statement I and Statement II are correct. | 
| 4. | Both Statement I and Statement II are incorrect. | 
| 1. | Stratification | 2. | Scarification | 
| 3. | Standing crop | 4. | Standing state |