Question

Visceral mass is segmented in
A. Neopilina
B. Aplysia
C. Dentalium
D. Xancus

Answer 1

Hint: The digestive, reproductive, excretory, and respiratory systems are all housed in the visceral hump, or visceral mass, of gastropods, which is often enclosed within the shell. The mantle, or pallial, cavity makes up a large portion of the visceral hump.

Complete answer:
Molluscs have a muscular foot that is used for locomotion and anchorage. The form and function of this foot differs depending on the type of mollusc being studied. This foot is normally the same size as the opening of the shell in shelled molluscs. The foot is both a retractable and expandable organ.
The foot is the most ventral organ, while the mantle is the most dorsal. While molluscs are acoelomates, the coelomic cavity in adult animals is limited to a cavity around the heart. The coelomic cavity and the mantle cavity form independently.
The visceral mass can be found in the visceral hump, which is located above the foot. The digestive, nervous, excretory, reproductive, and respiratory systems are also included in this. Gills are used for respiration in aquatic molluscs, while lungs are used by some terrestrial molluscs.
In molluscs, the body is usually unsegmented, but the head, muscular foot, and visceral mass/hump are distinct, but the internal organs are not.
However, Monoplacophora, also known as a living fossil, is segmented; Neopilina is an example of Monoplacophora, and it represents segmented internal organs.

So the correct answer is option A

Note:
The mantle, which is made up of two flaps that secrete the material that forms the shell and covers the mantle cavity, is also part of the visceral hump. The gills, which excrete waste and circulate oxygen, are located in the mantle cavity.