The liquid portion of blood is :

The liquid portion of blood is
 
  A) serum.
  B) plasma.
  C) water.
  D) lymph.

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A white blood cell that protects the body against infection is a
 
  A) formed element.
  B) platelet.
  C) leukocyte.
  D) erythrocyte.

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Which type of blood cell transports oxygen?
 
  A) lymphocyte
  B) platelet
  C) leukocyte
  D) erythrocyte

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A mass of lymphoid tissue along a lymphatic vessel that filters bacteria and other foreign substances is a
 
  A) leukocyte.
  B) lymphocyte.
  C) lymph node.
  D) tonsil.

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Which type of blood vessel carries blood toward the heart?
 
  A) Vein
  B) Artery
  C) Venule
  D) Arteriole