D: Empty space.
No, gases have more empty spaces.
Gases
Democritus
the molecules of gases are spread out very far apart and are not being restricted like solids or liquids
robert boyle
Very probable this space is empty, is vacuum.
all of them are; except, empty space can only be a medium to electromagnetic waves
well solids would be particuls all compact then liquads would be less compact and so on for gases... this usually occurs from van der walls forces breaking from heating and then there is just empty space between particles that are in a gas form
The emptiness of space is made of nothing -- absolutely nothing. There are various particles, chunks of rock, dust and gases, but they are made of matter. The space itself is just space. Lots and lots of space.
slow down and refract
Yes. Gases are very compressible because there is a lot of empty space between the molecules. A liquid has almost no empty space between the molecules. When compressing a gas you are pushing the molecules closer together, getting rid of some of the empty space. Can't do that with liquids. Example 18grams of liquid ware will occupy 18 ml or 0.018 Liter of space (volume). Boil that same 18 grams of water and it will occupy about 24000 ml or 24 Liters of space because in the gas form the same number of molecules are farther apart with lots of empty space between them .