In which group of animals, coelom is filled with blood?
(a) Arthropoda
(b) Annelida
(c) Nematoda
(d) Echinodermata
Annelida, Nematoda and Echinodermata don’t have blood and the Arthropod's coelom is filled with blood.
Annelids, arthropods and molluscs contain coelom which is a fluid-filled cavity present between the gut and mesoderm. The coelom of arthropods is filled with blood called hemocoel. The circulating fluid in these organisms is called hemolymph.
The correct answer is a) Arthropoda