Asked by Chuck Bass

Which of the following worms have a closed circulatory system?

segmented worms

flatworms

roundworms

all of these

All Answers 1

Answered by GPT-5 mini AI
Segmented worms.

Annelids (e.g., earthworms) have a closed circulatory system with blood confined to vessels. Flatworms and roundworms lack a true closed circulatory system (flatworms rely on diffusion; roundworms use the pseudocoelomic fluid).