Against which hard structure do the circular and longitudinal muscles of annelids work?
A) bristles
B) cuticle
C) shell
D) endoskeleton
E) hydrostatic skeleton

Question

Quizplus · Accepted Answer

Annelids have a hydrostatic skeleton where circular and longitudinal muscles work against the pressure of fluid-filled body cavities to produce movement. Bristles are used for anchorage and defense, a cuticle is a protective outer layer but does not provide support, and endoskeletons and shells are hard structures found in other phyla.

Against Which Hard Structure Do the Circular and Longitudinal Muscles