Final answer:
A mixture with particles not spread out evenly is a heterogeneous mixture, unlike homogeneous mixtures, which have a uniform composition.
Step-by-step explanation:
The type of mixture that contains particles that are not spread out evenly is a heterogeneous mixture. An example of this would be orange juice with pulp, where the composition is not uniform throughout. Conversely, a homogeneous mixture, also known as a solution, has a uniform composition throughout, like salt dissolved in water where you cannot see the individual salt particles.