The element essential for the formation of hemoglobin in blood is iron (Fe). Hemoglobin is a protein in red blood cells responsible for transporting oxygen from the lungs to tissues and returning carbon dioxide from tissues back to the lungs. Iron is a crucial component of hemoglobin, giving blood its red color and enabling its oxygen-carrying capacity. A deficiency in iron can lead to anemia, resulting in fatigue and decreased oxygen delivery to tissues. Including iron-rich foods like red meat, beans, and spinach in the diet is vital for maintaining adequate hemoglobin levels and overall health.