Answer: A compound
Explanation: A compound is a substance that is made up of two or more elements that are combined chemically and can be separated only by chemical means.
The properties of a compound differ from the properties of its constituent elements. For instance carbon dioxide (CO2) is made up of carbon and oxygen atoms. The properties of carbon dioxide is different from the individual properties of carbon and oxygen.
Compound are made up of elements that are combined in a specific ratio. The ratio of carbon to oxygen in Carbon dioxide is 1 : 2. This means that there are one carbon atom (C) and two oxygen atoms (O2) in one molecule of carbon dioxide (CO2).