What is the approximate length of the alimentary canal in adult human beings?

The alimentary canal, also known as the gastrointestinal tract or digestive tract, is a complex system of organs responsible for breaking down and absorbing food. It begins at the mouth and extends all the way to the anus, comprising various segments such as the mouth, pharynx, oesophagus, stomach, small intestine, large intestine, rectum, and anus.

In adult human beings, the length of the alimentary canal can vary depending on factors such as age, diet, and health status. On average, however, the length of the alimentary canal is approximately 30 feet or 9 meters long. This length is essential for the proper digestion and absorption of nutrients from the food we eat.

Therefore, the correct answer is 9 meters long.