Answer the following question given this paragraph: 

Hemoglobin Hemoglobin is a large molecule made up of proteins and iron. It consists of four folded chains of a protein called globin, designated alpha 1 and 2, and beta 1 and 2 (Figure 18.7a). Each of these globin molecules is bound to a red pigment molecule called heme, which contains an ion of iron (Fe2+) (Figure 18.7b).


Q: Hemoglobin is a large molecule made up of proteins and iron. it consists of four folded chains of a protein called this?

 Choices:

- peptide

- histone

- insulin

- globin

A:
globin
