Answer the following question given this paragraph: 

Besides water, most of the compounds in living things are biochemical compounds. A biochemical compound is a carbon-based compound that is found in living organisms. Carbon is an element that has a tremendous ability to form large compounds. Each atom of carbon can form four chemical bonds with other atoms. A chemical bond is the sharing of electrons between atoms. Bonds hold the atoms together in chemical compounds. A carbon atom can form bonds with other carbon atoms or with atoms of other elements.


Q: What element is a biochemical compound based on?

 Choices:

- hydrogen

- nitrogen

- oxygen

- carbon

A:
carbon
