Final answer:
Myoglobin contains four heme groups and can bind and transport oxygen in muscle cells.
Step-by-step explanation:
The correct statement about the myoglobin structure is that it contains four heme groups. Myoglobin is a relatively small protein that contains an iron-porphyrin complex called heme. This heme group has a vacant coordination site where oxygen binds. Therefore, myoglobin can bind and transport oxygen in muscle cells.