The label on a bottle of shampoo lists many ingredients, such as water, sodium laureth sulfate, lauramide dea, sodium chloride, etc. from this information, shampoo is best classified as

Colloids

Explanation:

Colloids are heterogeneous mixtures that have at least two phases, one well-divided phase (solid, gaseous or liquid) called the dispersed phase and the continuous phase called the dispersion medium. These systems have particles generally smaller than 1000 nanometers (1 nanometer = 1 nm = 10⁻⁹m).

Simply by the human eye, colloids may appear to be homogeneous mixtures, but microscopically, their particles do not mix, constituting more than one phase(heterogeneous).

In addition to shampoo, there are other examples of colloids such as gelatin, fog and sour cream.