Question

Which of the following is a locomotory organ in the snail?
A. Outer shell
B. Muscular foot
C. Muscular rings
D. All of the above

Answer 1

Hint: Snails are a class of invertebrates that are covered by a coiled shell. They belong to the class Gastropoda under the phylum Mollusca. Snails move with the help of muscular contraction of the underside of their body.

Complete answer:
Snails are gastropods with a soft body covered by a hard shell. The shell of a snail is a spiral or coiled structure composed of calcium carbonate. The shells comprise three layers and serve as a protective covering for the soft bodied animal. It also protects the snails from predators. The outer shell in various species of snails vary in their designs and shapes, but the spiral nature remains constant in all the gastropods.
All snails move by muscular contractions and relaxations of a ‘foot’ present on the underside of the body of snails. The ventral foot undergoes muscle contractions from its posterior end to the anterior end. The snail secretes a layer of mucus that acts as a lubricant to avoid friction. Therefore, it can be said that the locomotory organ of the snail is a muscular foot.
Muscular rings are generally present in earthworms. The body of an earthworm is divided into many segments. Each segment comprises a muscular ring. The contraction and relaxation of the muscular rings help the earthworm to locomote.
Therefore, we can conclude that the snails move with the help of their muscular foot.

Hence, option (b) is correct.

Note: Snails belong to the phylum Mollusca. They are soft bodied animals covered by a coiled shell made of calcium carbonate. The snails move with the help of muscular contractions of a muscular foot present on the ventral side of its body. The animal secretes a mucus layer to reduce friction with the hard surface on which it is moving.