Which of the following is a heterogeneous mixture

Heterogeneous Mixtures aren't uniform and are separated in the mixture. They are usually more easily able to be separated. An example is milk and cereal. The cereal isn't uniform because the milk and cereal still are separated and have their own identities. (You can easily just remove cereal from milk using a strainer)

Homogeneous Mixtures are uniform in composition and the multiple elements have become one solution. These mixtures are hard to separate into their components. An example is tap water because it contains water as well as various minerals that can only be separated by performing chemical reactions.