The structure that allows the exchange of gases and nutrients between the mother and fetus is the: MCQ with Answer and Explanation

Explanation:
The stomach secretes gastric juice containing hydrochloric acid and the enzyme pepsin, which initiates the digestion of proteins into smaller peptides. The small intestine is the primary site for the final digestion of food and the absorption of most nutrients (amino acids, simple sugars, fatty acids, vitamins) into the bloodstream through its villi. The large intestine (colon) primarily absorbs water, electrolytes, and some vitamins produced by gut bacteria, forming solid feces. All statements are correct.

Explanation:
Villi are microscopic finger-like projections on the inner lining of the small intestine, covered with microvilli (brush border), greatly increasing surface area for absorption of digested nutrients. Each villus contains a lacteal (lymph capillary) and blood capillaries. Alveoli are in lungs, nephrons in kidneys, cilia are hair-like projections on cells.

Explanation:
About 70% CO₂ is carried as bicarbonate. The main stimulus is high CO₂; external respiration is in lungs; diaphragm moves downward (contracts) during inhalation.