(i) Transport of oxygen. The haemoglobin present in the red blood calls takes the oxygen
from alveoli of the lungs. The oxygen is carried by blood to all parts of the body. As the
blood passes through the tissues of the body, the oxygen from the blood diffuses into
the cells.
(ii) Transport of carbon dioxide. Carbon dioxide is more soluble in water. it is present in
our blood plasma in a dissolved state and is transported from the bosy tissues to lungs
where it diffuses from blood to air in the lungs and then expelled out theough nostrils
during exhaling.
