What food is the richest source of the vitamin or mineral ions essential for the transport of oxygen by the blood?

The richest source of iron, which is essential for the transport of oxygen by the blood, is red meat, particularly beef and lamb. Other good sources include organ meats like liver, as well as legumes, spinach, and fortified cereals. Iron is a critical component of hemoglobin in red blood cells, enabling them to carry oxygen throughout the body.