Adding salt to a liquid decreases the melting point of that liquid, and the addition of salt increases the density of water. Given these facts, what decreases the melting point of water among the following options:
- The bending of a ray of light
 - heating liquids
 - cloudy and rainy weather
 - Movement of an air mass
 - increasing its density
 - global warming
 - tectonic plates coliding
 - movement of tectonic plates


 

     increasing its density    