The ratio of hydrogen and oxygen by mass in a molecule of water is :

1. 1:16
2. 2:8
3. 1:8
4. 8:1

Sea water contains a large amount of:

1. suspended impurities
2. disolved common salt
3. oily substances
4. none of the above

Water retuns on earth's surface from the atmosphere by the process of:

1. combustion
2. respiration
3. photosynthesis
4. condensation

Spring water is classified as:

1. surface water
2. above surface water
3. underground water
4. none of these