An animal without an anus is

Endoparasites are found inside the host body. Mention the special structure possessed by these and which enables them to survive in those conditions.

What is the covering present around the body of parasitic animals belonging to the phyla Platyhelminthes and Nematoda?

Give a scientific reason: Having a flat body is an advantage among flatworms.

The characteristics of a tapeworm are:
$(A)$ Large,quadrate scolex,without rostellum and hooks
$(B)$ Primary host man,and secondary host cattle
$(C)$ Length $5$ to $10$ metres
Identify the tapeworm.

Which of the following organisms has only a single opening that serves as both the mouth and the anus?