How is air defined in terms of composition?

Air is defined as a mixture of gases that occupy the same space. This definition is accurate because air is primarily composed of several gases, including nitrogen, oxygen, carbon dioxide, and trace amounts of other gases. These components do not chemically combine in a fixed ratio, allowing them to be classified as a mixture.

Given the context of air, the understanding that it occupies the same space is crucial, as gases can freely move and mix with one another. This characteristic makes air an important element in various processes, including those involved in fire, drying, and other environmental contexts relevant in commercial drying practices.

The other options do not correctly define air: a single compound made of nitrogen is not accurate, as nitrogen is only one component of air. Labeling air as a solid with gaseous elements misrepresents its state, and describing it as a homogeneous mixture of liquids is incorrect, as air does not consist of liquid components.