Rhabdites occur inA. Planaria/DugesiaB. FasciolaC. TaeniaD. Echinococcus

Rhabdites are specialized structures found in certain types of flatworms, specifically in turbellarians like Planaria (Dugesia). These are rod-shaped cells found in the epidermis of the organism, and they play a role in secreting mucous to help in locomotion and protection.

Let's break down each option:

A. Planaria/Dugesia – Rhabdites are present in these organisms, which are free-living flatworms belonging to the class Turbellaria.

B. Fasciola – This is a genus of parasitic flatworms, also known as liver flukes. They do not have rhabdites.

C. Taenia – This is a genus of parasitic flatworms, known as tapeworms. They do not have rhabdites.

D. Echinococcus – This is a genus of parasitic flatworms, also known as the dog tapeworm. They do not have rhabdites.

Therefore, the correct answer is:

A. Planaria/Dugesia