Across
- 4. The toxic, air polluting gas that causes acid rain is --------
- 5. Colour of liquid oxygen is -------
- 9. The excessive growth of algae in lakes causing harm to other living things is called ---------
- 11. 78% of total air is ----------
- 12. --------- is an inert gas that makes up about 0.97%
Down
- 1. --------- is an effect of air pollution
- 2. The substances that contaminate the air are called ---------
- 3. Natural cause of air pollution
- 6. Presence of undesirable components in the air causes -------
- 7. ---------- forms 21% of total air.
- 8. --------- layer protects the living organism from UV rays
- 10. ----------- is composed of many gases