H2 is a covalent bond. Each hydrogen atom shares its single electron to the other, so each hydrogen has two valence electrons (full outer shell).
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.
The population would decrease, the more predators there are the more food needed for the species .
