1. Which of the following structures is not a part of the alimentary canal? A) Mouth B) Esophagus C) Gallbladder D) Stomach Answer: C) Gallbladder Rationale: The gallbladder is an accessory digestive organ that stores bile, not a part of the alimentary canal which includes the mouth, esophagus, stomach, and intestines. 2. The process of breaking down food into molecular particles of usable size and content is known as: A) Ingestion B) Digestion C) Absorption D) Secretion Answer: B) Digestion Rationale: Digestion refers to the chemical and mechanical process of breaking down food into smaller components that can be absorbed into the bloodstream. 3. Which layer of the gastrointestinal tract is responsible for peristalsis and segmentation? A) Mucosa B) Submucosa C) Muscularis externa D) Serosa Answer: C) Muscularis externa Rationale: The muscularis externa is responsible for the rhythmic contractions known as peristalsis and segmentation that propel food through the digestive system. 4. What is the primary function of the small intestine? A) To process waste material B) To absorb nutrients C) To produce digestive enzymes D) To store undigested food Answer: B) To absorb nutrients