Final answer:
The statement is false because not all water is added to the body through the digestive tract; approximately 10 percent is produced endogenously during cellular metabolism. Most water is absorbed through the small intestine, with the remaining amount absorbed in the colon.
Step-by-step explanation:
The statement that water is added to the body only through the digestive tract is false. While most water intake occurs through the consumption of liquids and foods that pass through the digestive tract, not all water enters the body this way.
A significant amount of water, approximately 10 percent, is produced endogenously as a byproduct of aerobic respiration during cellular metabolism. Within the digestive system, water is essential for various functions. About nine liters of fluid enter the small intestine daily, coming from ingested food and beverages as well as gastrointestinal (GI) secretions.
Around 90 percent of this water is absorbed in the small intestine, and the remaining is absorbed in the colon, helping to form feces in the process. Furthermore, large quantities of water are excreted into the alimentary canal as part of digestive juices, with the vast majority being reabsorbed.
Thus, while water absorption in the digestive tract is crucial for maintaining fluid balance, the body also gains water from metabolic processes, highlighting the fact that the digestive tract is not the sole contributor to the body's water supply.