Question 1
Which of these organs does not act as an excretory organ?
The right answer is the one marked above.
The stomach. It digests food; it does not remove metabolic waste from the body.
The kidneys pass out urea, water and salts, the lungs CO2 and water vapour, and the skin water and salts as sweat. What leaves by way of the stomach is undigested food — it never entered the cells at all.