In a heterogeneous mixture, the components are mixed unevenly and you can see the different thing in the mixture, while in homogeneous mixture (aka solution), the parts are evenly mixed together.
The correct answer is that the components are mixed unevenly instead of evenly within the heterogeneous mixture.
A heterogeneous mixture basically refers to any kind of mixture, which is not uniform in composition. It is an uneven mixture of smaller component parts. In the heterogeneous mixture, with the help of certain procedures, the mixture can be separated from each other.
On the other hand, a homogeneous mixture refers to a liquid, solid, or gaseous mixture, which exhibits the similar ratios of its constituents all through a given sample.