The question is like asking "what's the difference between a red shirt and one made of nylon"? Superconductors are also solids. I don't think there are any liquid or gaseous superconductors (weird stuff may happen in portions of the phase diagram far removed from ordinary Earthly conditions, so I'm not absolutely positive that, say, liquid metallic hydrogen or whatever isn't superconducting, but any superconductors we can actually make on Earth are solids).
gasses
Gases, liquids and solid all have different consistencies (densities). So the sound is changed
Solid
As compared to liquids or gasses, yes they are.
it is more spread out
Acid is not any single substance but a "family of substances. There are many different acids. Some are solids, some are liquids, some are gasses.
Liquids CAN be compressed ... but not as much as gasses, nor as easily. The reason is that there is no "free space" between the molecules of a liquid (nor of a solid), but there is between the molecules of a gas.
Humans are a mixture of liquids and solids with small amounts of dissolved gasses.
Are they liquids? Are they gasses? Cookies and muffins seem pretty solid to me. Unfortunately, they seem to make me more solid as well.
No. First of all, liquids are not gasses. Liquids and gasses are two different states of matter. Second, you can have any mass of liquid or any mass of gas. Third, liquids are denser than gasses, meaning they have more mass for a given unit of volume.
Liquids have the form of the containers.
No. Air is an example of a mixture of gasses. Brass is an example of a mixture of two solid metals.