Here's why:

* Compound: A compound is formed when two or more different elements chemically combine in a fixed ratio. Sulfuric acid (H₂SO₄) is made up of hydrogen (H), sulfur (S), and oxygen (O) atoms bonded together.

* Mixture: A mixture is a combination of two or more substances that are not chemically bonded. The components of a mixture can be separated by physical means.

* Element: An element is a pure substance that cannot be broken down into simpler substances by chemical means.

Since sulfuric acid is formed by the chemical combination of hydrogen, sulfur, and oxygen, it is a compound.