BBC3 年
The structure of the digestive system
The intestines have lots of tiny folds in them which create a large surface area for absorbing nutrients and water. In the small intestine there are also specialised structures called villi which ...
BBC3 年
The structure of the digestive system
The intestines have lots of tiny folds in them which create a large surface area for absorbing nutrients and water. In the small intestine there are also specialised structures called villi which ...