Which anatomical regions are the primary habitats where the gut microbiome resides?

• A. Stomach and esophagus where most fermentation and microbial vitamin production occurs due to slower transit time and acidic fermentation niches.
• B. Duodenum and jejunum where most microbes colonize because of high stomach acid neutralization and pancreatic enzyme inactivation.
• C. Large intestine (colon) and the terminal ileum of the small intestine.
• D. Gallbladder and bile ducts where microbes are concentrated because bile salts support bacterial growth and form an ecosystem analogous to the microbiome.

Answer: (C)