AP BIOLOGY

Detailed explanation-1: -Hemoglobin is the protein inside red blood cells. It carries oxygen.

Detailed explanation-2: -Hemoglobin is the protein that carries oxygen and exists within each red blood cell.

Detailed explanation-3: -How does oxygen get into the bloodstream? Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body.

Detailed explanation-4: -Red blood cells contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body.