Answer:
when matter is heated or cooled it melts or freezes for at least the atoms do
Explanation:
for example take water when you heat it up the water molecules melt producing vapor water vapor and when you freeze it or cool it down it turns into liquid or turned into a solid by turning into ice. the three main properties of matter are gas liquid and solid and if we put water into these three different categories it turns into water vapor as gas liquid water as liquid and Ice as a solid
hope this helps