Which description best matches the nematode digestive system?

Which description best matches the nematode digestive system?

• A. Alimentary canal, one way
• B. Complete digestive tract with two openings
• C. Digestive sac with a single opening
• D. No digestive tract

Answer: (A)

The key idea is that nematodes have a true digestive tube that runs from mouth to anus, allowing food to move in one direction through the body. This setup is called an alimentary canal. It’s a complete digestive tract with two openings, which is what keeps digestion and absorption moving forward as material passes along the tube. Describing it as an alimentary canal, one way, highlights both the tubular nature of the gut and the unidirectional flow of contents, which fits how nematodes process food. In contrast, a digestive sac with a single opening would imply two-way digestion through one opening, and no digestive tract would be incorrect for nematodes.

The key idea is that nematodes have a true digestive tube that runs from mouth to anus, allowing food to move in one direction through the body. This setup is called an alimentary canal. It’s a complete digestive tract with two openings, which is what keeps digestion and absorption moving forward as material passes along the tube. Describing it as an alimentary canal, one way, highlights both the tubular nature of the gut and the unidirectional flow of contents, which fits how nematodes process food. In contrast, a digestive sac with a single opening would imply two-way digestion through one opening, and no digestive tract would be incorrect for nematodes.