How do the alveoli of lungs in human body help in the exchange of gases?

(Q.11)  How do the alveoli of lungs in human body help in the exchange of gases?

(A) Alveoli provide a surface for the exchange of gases. (B) Alveoli do not provide any surface. (C) Alveoli bring gases from nostrils to the lungs. (D) Alveoli bring gases from lungs to the nostrils. (Q.12)  What does small intestine receive to digest carbohydrates, proteins & fats?

(A) Secretions from liver (B) Secretions from pancreas (C) Both of the above (D) Secretions from the stomach (Q.13)  Molecular movements are needed for life:

(A) For repairing and maintaining structures (B) For Nutrition (C) For Respiration (D) For Repairing (Q.14)  Element present in all the Life forms on earth:

(A) Oxygen (B) Nitrogen (C) Sodium (D) Carbon (Q.15)  Enzymes are:

(A) Vitamins (B) Proteins (C) Carbohydrates (D) Fats