Answer the following question given this paragraph: 

Four interactions stabilize the tertiary structure of a protein: (a) ionic bonding, (b) hydrogen bonding, (c) disulfide linkages, and (d) dispersion forces. When a protein contains more than one polypeptide chain, each chain is called asubunit. The arrangement of multiple subunits represents a fourth level of structure, the quaternary structure of a protein. Hemoglobin, with four polypeptide chains or subunits, is the most frequently cited example of a protein having quaternary structure Saylor URL: http://www. saylor. org/books.


Q: Hemoglobin, with four polypeptide chains or subunits, is the most frequently cited example of a protein having what kind of structure?

 Choices:

- binary

- unary

- ternary

- quaternary

A:
quaternary
