Answer:
Milk
Explanation:
Milk is what we call colloid.
A colloid is, basically, a substance that has a homegenous appereance in naked eye. But with some pressure on it or looking into a good microscope, we can see other particles, other pure substances.
In the case of milk, we have fat, proteins, water and a few other things.
Table salt, rubbing alcohol and Rust on a nail are all pure substances, because they have only one type of atoms arrangement, respectively:
NaCl - a "crystal" - , Fe(OH)³ - other "crystal" -, and C3H8O - who has a classic geometric form.
