True solutions, or homogenous solutions, exist as air, oxygen and brass, and are mixtures that contain two or more substances. Homogenous solutions can be broken down into separate substances, and the substances used to form them vary according to the amount of each that is used to create the complete solution.
Homogenous solutions exist in several different states, but are most commonly found as liquids. Some solutions are made of gases and solids as well, however; air is one of the most prevalent examples of a gaseous homogenous solution. Air is comprised of the elements of oxygen and nitrogen, and contains trivial amounts of other gases. Brass is an example of a solid homogenous solution, and is made of zinc and copper.