* Mixture: A combination of two or more substances where each substance retains its own properties. The components of a mixture can be separated by physical means.

* Compound: A substance formed when two or more elements chemically combine in a fixed ratio.

Paper is made from wood pulp, which is a complex mixture of cellulose fibers, lignin, and other substances. These components can be separated by physical means, like dissolving the lignin or extracting the cellulose fibers.

Since paper is a combination of multiple substances that can be separated by physical means, it is classified as a mixture.