Question

question 7
why is the hemoglobin molecule considered to have a quaternary protein structure?
answer
it has four major functions in the human body.
it is fibrous and generally insoluble in body fluids.
its four subunits react independently of each other.
it has four separate, but interacting, polypeptide subunits.
i dont know yet

Explanation:

Quaternary protein structure is defined by the presence of multiple separate, yet interacting, polypeptide subunits. Hemoglobin has four such subunits, which is why it has a quaternary structure.

Answer:

It has four separate, but interacting, polypeptide subunits.