This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Nutrients are mainly absorbed in: 
Select and explain. 
A. Small intestine, B. Large intestine, C. Liver, D. Stomach
A: Small intestine
Answer: A: Small intestine 
Explanation: Proteins, carbohydrates, fats and other nutritive substances like vitamins, and minerals are absorbed mostly in small intestine.
In the small intestine, secondary active transport of Na+ is important in bringing about absorption of glucose, some amino acids, and other substances such as bile acids.
Reference: GUYTON AND HALL TEXTBOOK OF MEDICAL PHYSIOLOGY, THIRTEENTH EDITION(INTERNATIONAL EDITION ) page no 464