Q. Which among the given statements is right?
✅ Correct Answer: (A)
flat worms are with parenchymal circulation
Explanation:
Flatworms (Platyhelminthes) do not have a circulatory system. Instead, they rely on parenchymal circulation, where nutrients and gases diffuse through the parenchyma (a type of tissue that fills their body).
- Sponges (Porifera) have a canal system for water circulation, making option (B) also correct, depending on the context.
- Nematodes (Roundworms) have a pseudocoelomic fluid that helps in circulation, but they do not rely on parenchymal circulation.
- Echinoderms (like starfish) have a water vascular system, not pseudocoelomic circulation.
So, A is the best answer, though B is also a factually correct statement.
Explanation by: Official MCQ Buddy
Flatworms (Platyhelminthes) do not have a circulatory system. Instead, they rely on parenchymal circulation, where nutrients and gases diffuse through the parenchyma (a type of tissue that fills their body).
- Sponges (Porifera) have a canal system for water circulation, making option (B) also correct, depending on the context.
- Nematodes (Roundworms) have a pseudocoelomic fluid that helps in circulation, but they do not rely on parenchymal circulation.
- Echinoderms (like starfish) have a water vascular system, not pseudocoelomic circulation.
So, A is the best answer, though B is also a factually correct statement.