A mantle and mantle cavity are present in:

a. phylum Echinodermata.

b. phylum Adversoidea.

c. phylum Mollusca.

d. phylum Nemertea.

The Mantle is an exterior layer made of soft, squishy brachiopods and molluscs that is occasionally fortified by calcified plates made of barnacles. The mantle cavity is the name for the mantle's hollow.

One of the key components of molluscan biology is the mantle cavity. The mantle skirt, a double fold of the mantle that encloses a water space, creates this cavity. The gonopores, nephridiopores, anus, and osphradium of the mollusc are all located in this region. Most molluscs have a mantle cavity that serves as a respiratory chamber.

Sea urchins, brittle stars, sea cucumbers, and sand dollars are all members of the phylum Echinodermata. They have an ossicular endoskeleton that is comprised of calcareous material. They lack the mantle and the mantle cavity. Adversoidea is a name that no phylum has.

Due to the presence of a proboscis that is enclosed in a rhynchocoel, the phylum Nemertea, commonly known as ribbon worms, is distinctive. The proboscis is used by members of this phylum to catch food. The mantle and mantle cavity is absent in this phylum as well.