Fill in the blank spaces by choosing the correct words from the given list.
List: oxygen, carbonic, suIphur dioxide gas, precipitation, helium
1. ...............gas can cause acid rain.
2. Every nine parts of water by weight contains eight parts by weight of................
3. Dust particles help in the................ of water vapor in air.
4. ...............gas is used for filling weather observation balloons.
5. Solution of carbon dioxide in water is called............. acid.