Answer:
Fluke
Explanation:
A fluke is referred to as trematode, a type of parasitic worm that belong to phylum plathyhelminthes. A fluke has a flattened body structure with about few centimetres long. Flukes do not possess an excretory system, but possess a digestive tract with just one opening that serves as both mouth and anus. Also, they do not posses respiratory organs .
Flukes possess a body surface that enables it inhabit the digestive system of larger animals and also avoid the effect of digestive enzymes.
These parasitic worms can be found to infect vertebrates and molluscs, such as snails. An example of a fluke is Schistosoma haematobium.
