Answer the following question given this paragraph: 

A snowflake is made of ice, or water in the solid state. A solid is one of four well-known states of matter. The other three states are liquid, gas, and plasma. Compared with these other states of matter, solids have particles that are much more tightly packed together. The particles are held rigidly in place by all the other particles around them so they can’t slip past one another or move apart. This gives solids a fixed shape and a fixed volume.


Q: What state of matter completes the list: solid, liquid, gas?


A:
plasma