Which of the following statements is correct about the flatworms?
A) Flatworms have three complete tissue layers.
B) Flatworms may be either free living or parasitic.
C) Flatworms have a sac body plan, with only a mouth and no anus.
D) Most planaria are found in marine environments, but some dwell in freshwater and moist terrestrial environments.
E) All of the answer choices describe flatworms.

Question

Quizplus · Accepted Answer

Flatworms indeed have three tissue layers (ectoderm, mesoderm, and endoderm), making them triploblastic. They can be free-living or parasitic, showcasing a diverse lifestyle. Their body plan is a sac-like structure with a mouth but no anus, leading to a gastrovascular cavity for digestion. While many flatworms, including planarians, are found in marine environments, some do inhabit freshwater and moist terrestrial areas, demonstrating their adaptability to various habitats.

Which of the Following Statements Is Correct About the Flatworms