The necessity of water:

• All organisms require water to sustain their vital functions.
• Cells contain water.
• Plants receive nutrients with water.

The qualities of water:

• Water can store a lot of heat.
• Water conducts heat well.

The water cycle:

• Water is evaporated from water systems → water vapor → clouds → precipitation (rain) → rivers, lakes, groundwater → water flows back into the sea, if it does not evaporate before this.

Key words: water, salinity, heat, the water cycle.