Excretion refers to the removal of waste products that is produced from amino acids metabolism.
Carbon dioxide is formed in living organisms in the process of both aerobic respiration and anaerobic respiration and can be removed from the body through lungs.
Urea is produced in the liver and then the blood is to be sent to the kidney and which is excreted from the body.
Urea is compounds of nitrogen which is formed from amino acids that contains toxic substances which the body does not need.
