Which term describes two or more elements that have been chemically combined?

The correct term for two or more elements that have been chemically combined is "compound." Compounds are substances formed when atoms of different elements bond together through chemical reactions. This bonding involves the sharing or transferring of electrons, resulting in a new substance that has properties distinct from the individual elements that comprise it.

For example, water is a compound made up of hydrogen and oxygen atoms that are chemically bonded. The characteristic properties of water are very different from those of hydrogen and oxygen gases.

In contrast, an element refers to a pure substance that cannot be broken down into simpler substances by chemical means. A molecule refers specifically to a group of two or more atoms bonded together, but they can be made up of the same type of element (like O2, which is oxygen gas) or different elements. A mixture involves two or more substances that are physically combined, where each substance retains its own properties and can be separated by physical means. Therefore, the defining feature of a compound is that it results from the chemical combination of different elements, which is why this term is the most accurate choice for describing the process.