Question

Write about phylum mollusca?

Answer 1

They are bilaterally symmetrical.
They are triploblastic, which three layers.
They show organ system grade of organisation.
The body is soft and unsegmented.
Body is divisible into three regions – head, visceral mass and ventral foot.
Body is covered by a mantle and shell.

Answer 2

These animals have a soft, unsegmented body, with a hard, calcerous shell to protect their soft bodies. They have muscular foot to hep locomotion and also act as a weapon in some cases.

For example: snail, slug, oyster, mussel, clam, squid and octopus.
Hope this helps you.