What is the function of blood plasma, erythrocytes, leukocytes and platelets?

In the blood plasma, proteins are constantly present, including transport proteins. It ensures the dissolution of nutrients and the elimination of metabolic products.
Red blood cells are red cells. They contain hemoglobin – a protein that can carry oxygen and carbon dioxide. It is the red blood cells that deliver oxygen to every cell in the body.
Platelets are responsible for blood clotting. These cells prevent a person from losing too much blood as a result of a wound.
Leukocytes are white blood cells. Their role is to provide strong immunity, to protect the body from viruses, bacteria, fungi.

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