Step 1 - Briefly remembering the definition of homogeneous or heterogeneous
Homogeneous mixture ---> one cannot distinguish the components of the mixture. It is a one phase mixture, like water and sugar or water and salt.
Heterogeneous mixture ---> one can visibly distinguish the components of the mixture. It has one or more phases, like water and oil or water and sand
Step 2 - Answering the exercise
When we look at brass, we cannot distinguish the two substances from one another. Therefore, it is a homogeneous mixture. Also it is a solid solution.
Solid solutions are usually found in metal alloys.
Answer: homogeneous substance, solid solution