The answer choices for the first blank is:
 A. capillary
 B. heart
 C. lungs
 D. aorta
 The answer choices for the second blank is:
 A. arteriole
 B. vein
 C. ventricle
 D. atrium
 The answer choices for the third blank is:
 A. vein 
 B. arteriole
 C. ventricle
 D. artrium