Which description accurately defines roundworms?

Which description accurately defines roundworms?

• A. They have segmented bodies.
• B. They are unsegmented worms with cylindrical bodies.
• C. They have a shell around their bodies.
• D. They are primarily aquatic and have gills.

Answer: (C)

Roundworms are unsegmented, elongated worms with a cylindrical shape. They lack true body segments and are covered by a tough, flexible cuticle that they moult as they grow, rather than having any shell around them. The exterior is not a shell, but a cuticle, and many roundworms live in environments where respiration happens across their body surface rather than through gills. So the description that best fits them is unsegmented, cylindrical worms. The other ideas describe segmented bodies, a shell, or gill-based respiration, which don’t define nematodes.

Roundworms are unsegmented, elongated worms with a cylindrical shape. They lack true body segments and are covered by a tough, flexible cuticle that they moult as they grow, rather than having any shell around them. The exterior is not a shell, but a cuticle, and many roundworms live in environments where respiration happens across their body surface rather than through gills. So the description that best fits them is unsegmented, cylindrical worms. The other ideas describe segmented bodies, a shell, or gill-based respiration, which don’t define nematodes.