Explanation

The main constituent of hemoglobin is iron.

Hemoglobin transports oxygen and exhibits a quaternary protein structure.

Iron is crucial for hemoglobin formation; its deficiency can impact hemoglobin production.

Heme in hemoglobin is protoporphyrin IX.

Infants reach adult hemoglobin levels by the end of their first year.

Ferric ions are not part of hemoglobin.

Hemoglobin is found dissolved in plasma.