Question

Write three characteristics of phylum-Mollusca.

Answer 1

1. The bodies of these animals are soft and slimy. Hence, they are referred to as molluscs.
2. This is the second-largest phylum in the animal kingdom.
3. These animals are aquatic or terrestrial. Most of the aquatic molluscs are marine, but a few are freshwater dwellers too.
4. The body of these animals is triploblastic, eucoelomate, non-segmented, and soft. Except for animals like snails, their body shows bilateral symmetry. Their body is divided into three divisions, like the head, the foot, and the visceral mass.
5. The visceral mass is covered with a mantle. This mantle secretes a hard, calcareous shell. This shell may be external, internal, or even absent in some cases.
6. These animals are unisexual. Examples: Bivalve, Snail, Octopus, etc.