65. What is peristalsis?
(A) a process of fat emulsification in the small intestine
(B) voluntary control of the rectal sphincters regulating defecation
(C) the transport of nutrients to the liver through the hepatic portal vein
(D) smooth muscle contractions that move food through the alimentary canal
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統計: 尚無統計資料
統計: 尚無統計資料