The liver acts as an excretory organ by removing:

1. Each excretory organ removes a characteristic waste product. 2. The liver breaks down worn-out haemoglobin, and the pigment left over is excreted in bile. 3. Urea dissolved in water is excreted by the kidney as urine. 4. Carbon dioxide together with water vapour leaves through the lungs. 5. Water leaving through pores is sweat from the skin, so each of the other three belongs to a different organ. _Source: NECTA CSEE 2022 Biology 033, Question 1: Multiple Choice Items, item (iii)_