Food remains in the intestinal tract longer in axenic animals than in normal animals.

• A. True
• B. False
• C. Not enough data
• D. Depends on diet

Answer: (A)

The movement of contents through the gut is shaped by the presence of gut microbes. Normal animals with a healthy microbiota generate fermentation products, like short‑chain fatty acids, that help stimulate peristalsis and keep transit relatively efficient. In axenic (germ‑free) animals, the absence of these microbes means less fermentation and fewer pro‑motility signals, so the contents tend to move more slowly and remain in the intestinal tract longer. The enlarged cecum seen in germ‑free animals also reflects altered digestion and slower transit, supporting longer retention. So the statement is true.