Q: What is the name of the supportive structed that helps move a worm's muscles?


Read this paragraph and choose the correct option from the provided answers:

Segmented worms have a well-developed body cavity filled with fluid. This fluid-filled cavity serves as a hydroskeleton , a supportive structure that helps move the worm's muscles. Only the most primitive worms (the flatworms) lack a body cavity.

 Choices:

- spongin

- exoskeleton

- pollenation

- hydroskeleton


A:
hydroskeleton