Correct Answer: A

Rationale: The correct answer is A: bile. Bile acts as an emulsifier, breaking down fats into smaller droplets to aid in digestion and absorption. Trypsin is a digestive enzyme that acts on proteins, not fats. Lipase is an enzyme that breaks down fats, but it doesn't act as an emulsifier. Cholecystokinin (CCK) is a hormone that stimulates the release of digestive enzymes, including lipase, but it is not directly involved in emulsification.

Correct Answer: A

Rationale: The correct answer is pinocytosis. Pinocytosis is a process where cells in the small intestine absorb nutrients by engulfing them. This process is different from phagocytosis, which involves engulfing large particles, and excretion, which is the removal of waste products. Electrochemical diffusion is not directly involved in the absorption of food in the small intestine.

Correct Answer: C

Rationale: Probiotics are live bacteria that are beneficial for gut health and are often taken as supplements. They are not indigestible carbohydrates (Choice A), antibiotics (Choice B), or commercial fiber supplements (Choice D). Probiotics contain live strains of good bacteria that help maintain a healthy balance in the gut microbiome.

Correct Answer: D

Rationale: Eggs are considered a source of complete protein because they contain all the essential amino acids required by the body. The other options, cereal grains, beans, and nuts, do not provide all the essential amino acids in the necessary proportions to be classified as complete proteins.

Correct Answer: B

Rationale: The absorption of most nutrients occurs in the small intestine. This is where digested food is broken down further and absorbed into the bloodstream through the intestinal walls. The large intestine primarily absorbs water and electrolytes, while the stomach mainly aids in digestion by breaking down food with gastric juices. The mouth is responsible for the initial mechanical breakdown of food through chewing and the enzymatic action of saliva, but absorption does not occur there.