Fill in: antibodies, platelets, antigens, plasma. Check any unknown words in your dictionaries. Listen and check. Blood consists of red blood cells, white blood cells, 1) (small cells) and 2) (liquid part of blood). Antibodies and antigens in the blood identify your blood group.3) are proteins in plasma which protect the body from foreign substances in the blood such as germs. 4) are molecular on the surface of red blood cells that are molecules help produce antibodies.