Final answer:
A mantle and mantle cavity are characteristic features of the phylum Mollusca, distinguishing them from other invertebrate groups. The mantle secretes a shell in many species, and the mantle cavity contains gills for respiration in aquatic species, while it may serve as a respiratory organ in terrestrial mollusks. Therefore, the correct option is b) Molluska.
Step-by-step explanation:
A mantle and mantle cavity are present in the phylum Mollusca, which comprises a variety of invertebrate species living in marine, freshwater, and terrestrial environments. The mantle is a significant anatomical feature that covers the body and can secrete a protective calcareous shell in many mollusk species. Within the mantle, there is a space known as the mantle cavity, which is different from the coelomic cavity. The mantle cavity is the primary internal body chamber in mollusks—especially after the reduction of the coelomic cavity in adult animals. In aquatic mollusks, the mantle cavity houses gills, also known as ctenidia, which are used for respiration. Terrestrial mollusks may have the lining of the mantle cavity modified to serve as lungs. Overall, the presence of a mantle and a mantle cavity is one of the characteristic features that distinguish members of the phylum Mollusca from other animal phyla, such as Annelids, Arthropods, and Echinoderms.