| 1. | forming blooms in polluted water bodies |
| 2. | recycling nutrients like nitrogen, phosphorous, iron and sulphur |
| 3. | making curd from milk |
| 4. | fixing nitrogen in legume roots |
| I: | Phycomycetes |
| II: | Ascomycetes |
| III: | Basidiomycetes |
| 1. | a free RNA lacking a protein coat |
| 2. | a nucleocapsid |
| 3. | an abnormally folded protein |
| 4. | a ribozyme |