Answer :

Blood is a liquid and has cellular parts. The liquid contains substances such as proteins and lipids. The cellular constituents are erythrocytes (red blood cells), leukocytes and platelets.
Red Blood cells, as the Erythrocytes, are completely dedicated to their job of respiratory gas in the oxygen and carbon dioxide exchange.
White Blood cells, as the Leukocytes, crucial to our defense against disease, and as the platelets, essential for clotting process that occurs in plasma when blood vessels are ruptured or their lining injured. 
Hope this Helps :D i added their functions too just for more informations :)

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