1. air components change from place to place, while water will just stay the same
2. Water doesn't have nor show individual properties, but air does show that it has it's own property
3. You can separate different gases from air physically, but with water you must pass electricity through it.
Don't take my word for it, this is just what I learned back in middle school.
Troposphere, this is the layer of the atmosphere closest to the earths crust.
The most likely answer is the boiling point and freezing point of water. The Celsius scale starts at the freezing point of water (0°C) and than scaled so that 100°C fell on the boiling point of water.
I hope this helps. Let me know if anything is unclear.
Strongest reducing agents are in Group 1 . For example lithium. The strongest oxidising agents are in Group 7 , For example Fluorine.
