The answer is energy i am pretty sure
Answer:
B) venous blood and aveolar
Explanation:
Partial pressure of carbon dioxide in the aveolar is the lowest, it is 40mmHg (millimetre mecury ) while the partial of carbon dioxide in venous blood is the highest at 45 to 50 mmHg (millimetre mecury)
The ileum contains villi that project into the lumen and increase the amount of surface area.
Villi are small finger-like structures that project into the lumen of the small intestine. Villi increase the surface area of the intestinal walls for easy and quick absorption of digested food with the addition of digestive secretions. Villi vary in length from about 0.5 to 1 mm. They are usually found in large numbers at the beginning of the small intestine and they reduce toward the end of the tract.