Which of the following combinations will lead to the highest level of acid secretion through potentiation? (Potentiation refers to a post-receptor interaction where the response obtained is greater than the sum of each individual agent acting alone.)

Correct Answer: A

Rationale: Vagal input, histamine, and gastrin all stimulate parietal cells synergistically (potentiation), maximizing acid secretion, while secretin inhibits it.

Correct Answer: C

Rationale: Kupffer cells are specialized macrophages in the liver that remove debris and pathogens from the blood. Lymphocytes are white blood cells, and 'coffee cells' is not a term; 'liver macrophage' is less specific than Kupffer cells.

Correct Answer: A

Rationale: Fat breakdown products (fatty acids and glycerol) are lipid-soluble and can diffuse through the phospholipid bilayer of cell membranes.

Correct Answer: C

Rationale: Homeostasis maintains internal stability using nerves and hormones despite external changes.

Correct Answer: D

Rationale: The renal artery supplies blood to the kidney for filtration.