Here's why:

* Elements are the basic building blocks of matter, like oxygen, carbon, and hydrogen. While we find these elements in the world, they rarely exist in their pure form.

* Compounds are formed when two or more elements combine chemically. These combinations create new substances with different properties than the original elements.

Examples:

* Water (H₂O) is a compound made from hydrogen and oxygen.

* Carbon dioxide (CO₂) is a compound made from carbon and oxygen.

* Salt (NaCl) is a compound made from sodium and chlorine.

* Sugar (C₁₂H₂₂O₁₁) is a compound made from carbon, hydrogen, and oxygen.

While elements like oxygen and nitrogen are important components of the atmosphere, the vast majority of things we see and interact with are actually compounds. Even our bodies are made up of countless compounds!