text: <unk>  is a specialized biological fluid consisting of red<unk>  cells (also called RBCs or erythrocytes), white<unk>  cells (also called leukocytes) and platelets (also called thrombocytes) suspended in a complex fluid medium known as<unk>  plasma.
  By far the most abundant cells in<unk>  are red<unk>  cells. These contain hemoglobin which gives<unk>  its red color.  The iron-containing heme portion of Hemoglobin facilitates hemoglobin-bound transportation of oxygen and carbon dioxide by selectively binding to these respiratory gasses and greatly increasing their solubility in<unk> .  White<unk>  cells help to resist infections, and platelets are important in the clotting of<unk> .<unk>  is circulated around the body through<unk>  vessels by the pumping action of the heart.<unk>  is pumped from the strong left ventricle of the heart through arteries to peripheral tissues and returns to the right atrium of the heart through veins,<unk>  then enters the right ventricle and is pumped through the pulmonary artery to the lungs and returns to the left atrium through the pulmonary veins,<unk>  then enters the left ventricle to be circulated again. Arterial<unk>  carries oxygen from inhaled air in the lungs to all of the cells of the body, and venous<unk>  carries carbon dioxide, produced as a waste product of metabolism by cells, to the lungs to be exhaled.
  Medical terms related to<unk>  often begin with hemo- or hemato- (BE: haemo- and haemato-) from the Greek word "haima" for<unk> ."  Anatomically,<unk>  is considered a connective tissue from both its origin in the bones and its function.
option_0: Blood
option_1: Serum
option_2: Tissue 
option_3: Urine
option_4: Cord blood
option_5: Wound
option_6: Exudate
option_7: Sputum