The correct answer of Q1 is D. Aids in gas exchange.
The function of gas exchange is performed between lung’s alveoli and capillaries having blood located in the alveolar wall. So skin does not play any role in gas exchange. Therefore the correct answer is D. Aids in gas exchange.
The correct of Q2 is C. kidney
Kidney is the organ that helps in the filtration of blood. It clears the blood from impurities like urea, salt, steroids, and excess water. It does not play any role in digestion. So the correct answer is C. kidney.
The correct answer of Q3 is C. stomach
The stomach contains hydrochloric acid not hydroelectric acid and due to this hydrochloric acid the pH of the stomach is very low between 2-3.5. This pH is beneficial to kill pathogen comes with food. So the right answer is C. stomach.