*is scared to death when he feels the kunai pass by*
O_O SENSEI! What the...?!
*Getting back to my training, I explain what water is*.
Water is a substance that is within almost every aspect of the world we know today. Humans are said to be 60 - 90 % water, depending on the source that gives these number. The boiling point is 100°C, and the freezing point is 0 °C.
As for the Element water in the shinobi way:
Water is commonly know as Suiton (水遁). It is strong against fire, as it extinguishes fire, and weak against earth. Water can be combined with Lightning because it strenghtens the Lightning attacks enormously. It is possible to create water out of yourself (advanced mastery) or manipulate existing water (Beginner - Advanced Mastery)
There are also a lot of KG's at which water is one of the two base elements. For example there is Mokuton(木遁) or Wood release, where water and earth are combined. One of these users is The First Hokage, or Yamato.
Another example is Ice, more commonly known as Hyōton(氷遁), of which Haku is one of the only known users to have this kekkai genkai. Ice is believed to be a mixture of the Water and Wind element.
Does this suffice, Kirabi-Sensei?