Question

Why is the removal of faeces or undigested food from the body not an example of excretion?

Answer 1

Removal of faeces or undigested food from the body is not an example of excretion because undigested food is not a product of metabolism. Metabolic activities generate nitrogenous waste that has to be removed from the body. The biological process by which these harmful substances are removed from the body is known as excretion. Undigested food is removed from the body by a process known as egestion.