Concept:The digestive system includes all organs that help break down food and absorb nutrients.
Explanation:The oesophagus, stomach, and pancreas are all directly involved in digestion.
The oesophagus carries food from the mouth to the stomach.
The stomach churns food and mixes it with digestive juices.
The pancreas produces enzymes that help digest food.
The kidney, however, belongs to the excretory system.
It filters blood and produces urine instead of helping in digestion.
Therefore, the kidney is not an organ of the digestive system.
Answer:D. Kidney