Question

hemoglobin is a protein which binds to
carbon dioxide
proteins
oxygen
red blood cells

Explanation:

Hemoglobin is a protein in red blood cells. Its main function is to bind to oxygen in the lungs and transport it to the body's tissues. While it can also carry a small amount of carbon dioxide, its primary and well - known binding partner is oxygen. Proteins do not bind to hemoglobin in the context of its main transport function, and hemoglobin is located within red blood cells, not binding to them in the sense of a transport or functional binding.

Answer:

oxygen