Which one of the following has an open circulatory system?
- Octopus
- Pheretima
- Periplaneta
- Hirudinaria
Answer
(3) Periplaneta
Solution
As per NCERT, arthropods have an open circulatory system, while annelids and cephalopod molluscs have a closed type.
Periplaneta (cockroach, Arthropoda) — open circulatory system; haemolymph flows in open spaces (haemocoel).
Octopus (cephalopod), Pheretima (earthworm) and Hirudinaria (leech) — closed circulatory system.
Answer: (3)