Which statement about hemoglobin is correct?

Which statement about hemoglobin is correct?

• A. It carries oxygen in the blood.
• B. It is a type of white blood cell.
• C. It stores iron for later use.
• D. It regulates blood sugar levels.

Answer: (A)

Hemoglobin's main function is to transport oxygen in the bloodstream. In the lungs, iron in the heme part of hemoglobin binds oxygen; as red blood cells circulate, it releases that oxygen to tissues that need it, and it also helps carry carbon dioxide back to the lungs to be exhaled. This is why stating that hemoglobin carries oxygen is correct. It’s not a white blood cell but a protein inside red blood cells. Although iron is a component of hemoglobin, it doesn’t serve as an iron storage system—iron is stored by ferritin and related proteins. It also doesn’t regulate blood sugar; that function involves hormones and metabolism rather than hemoglobin.

Hemoglobin's main function is to transport oxygen in the bloodstream. In the lungs, iron in the heme part of hemoglobin binds oxygen; as red blood cells circulate, it releases that oxygen to tissues that need it, and it also helps carry carbon dioxide back to the lungs to be exhaled. This is why stating that hemoglobin carries oxygen is correct. It’s not a white blood cell but a protein inside red blood cells. Although iron is a component of hemoglobin, it doesn’t serve as an iron storage system—iron is stored by ferritin and related proteins. It also doesn’t regulate blood sugar; that function involves hormones and metabolism rather than hemoglobin.