Final answer:
A trematode is commonly referred to as a fluke. Flukes are internal parasites that infect mollusks and other groups, including humans. They have complex life cycles and cause serious diseases such as schistosomiasis.
Step-by-step explanation:
Flukes are a type of flatworm that have a leaflike appearance. They are internal parasites that infect mollusks and other groups, including humans. Flukes have complex life cycles that involve a primary host, usually a vertebrate, and one or more secondary hosts, typically mollusks. They are responsible for causing serious diseases such as schistosomiasis.