Answer:haemoglobin
Explanation:
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.
The answer is D.
The longer life expectancy
Hope this helps :)
Astronomers have seen stars forming within a nebular cloud. As the nebular cloud condenses and its own gravitational attraction collapses it, heat and energy build up creating a planet.
