Digestive tracts differ for different animals. - In comparisons ... Four functions of digestive system occur in different places. Proventriculus dumps fluid and acid into food just before it enters ...

Sponges are among the simplest animals, lacking a nervous system, brain, and digestive system. They filter water to get ...

Save guides, add subjects and pick up where you left off with your BBC account. The digestive system is like a big food factory inside our bodies. Its job is to break down the food we eat into ...

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