Biology / Unit 12 Bio 2789 short lesson, about 20 seconds
Four-Step Nutritional Process: Ingestion to Elimination
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The idea
Obtaining nutrition runs through four steps: ingestion, taking in food; digestion, breaking it into fragments; absorption, moving nutrients in; and elimination, removing waste.
In practice
Undigested plant fiber passes through all four steps without being absorbed, since the body lacks the enzyme to break it down.
Where people slip
Digestion and absorption are separate steps — a molecule can be fully digested yet fail to be absorbed.
Your place on the trail
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