Final answer:
Air is best described as a homogeneous mixture. This classification indicates that air is composed of various gases such as nitrogen, oxygen, and other trace gases, mixed uniformly. It is neither an element nor a compound.
Step-by-step explanation:
Air Composition Classification
When assessing the nature of air, the correct classification from the given options would be 'C. Mixture'. To be more specific, air is a homogeneous mixture made up of multiple substances, including primarily nitrogen and oxygen, as well as argon, carbon dioxide, and other trace gases, which are evenly distributed throughout the mixture. Air is not an element, because it consists of more than one kind of atom; it is not a compound, as its composition can vary and is not a single chemical substance with a fixed ratio of elements. Instead, air exemplifies a solution, which is a type of homogeneous mixture.
Examples of Elements, Compounds, and Mixtures
Salt is a compound (NaCl).
Pure water is a compound (H2O).
Soil is a heterogeneous mixture, composed of various organic and inorganic materials.
Salt water is a homogeneous mixture or a solution, where the salt is dissolved evenly in the water.
Pure air is a homogeneous mixture of gases.
Carbon dioxide (CO2) is a compound.
Gold is an element (Au).
Bronze is a metal alloy, a type of homogeneous mixture of copper and other metals like tin or aluminum.