Excretion — Science definition
Removing waste made by the body's own metabolism — carbon dioxide from respiration, urea from surplus amino acids — which is not the same as passing undigested food out.
Where it is taught
- Kidneys, Excretion & Internal Balance — Body Organization, Transport & Movement, Life Science & Scientific Inquiry, Grade 7
In use
Excretion is the removal of waste products made by the body's own chemistry — carbon dioxide from respiration, urea from breaking down surplus amino acids.
Kidneys, Excretion & Internal Balance
Questions using excretion
Problem 1
Why is excretion not identical to eliminating unabsorbed food?
Answer and explanation
Excretion removes wastes produced by metabolism; unabsorbed food is material that did not enter those cellular pathways.