H2O means water, which is made of two hydrogen and one oxygen atoms.
Oxygen is a gas that your body needs to function. Oxygen comes from the air.
Can you type it out the picture is too blurry to read, sorry.
A crystal is any solid that has an organized structure. ... So it is a prerequisite to be a crystal in order to be a mineral. All minerals, therefore, form crystals. On the other hand, there are crystals that are not minerals, because they are not naturally occuring, or because they are not inorganic
Source: http://www.geologyin.com/2016/03/what-is-difference-between-minerals-and.html?m=1