Upper digestive tract consists of （）.

A:duodenum B:esophagus C:oral cavity D:pharynx E:stomach

Upper digestive tract consists of （）.

A:duodenum B:esophagus C:oral cavity D:pharynx E:stomach

Upper digestive tract consists of （）.

A:duodenum B:esophagus C:oral cavity D:pharynx E:stomach

Upper digestive tract consists of （）.

A:duodenum B:esophagus C:oral cavity D:pharynx E:stomach

Upper digestive tract consists of （）.

A:duodenum B:esophagus C:oral cavity D:pharynx E:stomach