Final answer:
Hemoglobin is the protein in red blood cells that carries oxygen from the lungs to tissues, capable of carrying four oxygen molecules, and gives RBCs their red color. The correct option is c.
Step-by-step explanation:
The protein in red blood cells (RBCs) that carries oxygen from the lungs to the tissues is hemoglobin. Hemoglobin is a complex molecule made of four protein subunits and four iron-containing heme groups.
Each heme group can bind one molecule of oxygen, allowing a single hemoglobin molecule to carry up to four oxygen molecules.
This binding of oxygen results in the formation of oxyhemoglobin (HbO₂), which is responsible for the transport of oxygen throughout the body.
Hemoglobin also plays a role in the transport of carbon dioxide from the tissues back to the lungs. The iron in hemoglobin is what gives red blood cells their characteristic red color. The correct option is c.