The diagram shows part of the human digestive system - Edexcel - GCSE Biology - Question 6 - 2012 - Paper 1

The small intestine is responsible for the majority of nutrient absorption in the digestive process. It consists of three main parts: the duodenum, jejunum, and ileum. In the small intestine, food is mixed with bile from the liver and digestive juices from the pancreas, which contain enzymes that break down carbohydrates, proteins, and fats. The inner lining of the small intestine is covered with tiny hair-like structures called villi, which increase surface area and facilitate the absorption of nutrients into the bloodstream. Overall, the small intestine ensures that essential nutrients are absorbed effectively before the remaining waste moves on to the large intestine.