Question

Earthworms have no skeleton, but during burrowing, the anterior end becomes turgid and acts as a hydraulic skeleton. This is due to

• A. Setae
• B. Gut peristalsis
• C. Blood
• D. Coelomic fluid

Answer 1

The correct option is D

Coelomic fluid

Coelomic fluid serves as a hydrostatic skeleton and helps the muscles of the body wall in locomotion. When the circular muscles contract, the coelomic fluid provides stiffness to the body and the longitudinal muscles relax. When the earthworm holds the ground firmly, the circular muscles relax and the longitudinal muscles contract. Here, the coelomic fluid makes the region stiff which is behind the anterior region so that muscles can push the body forward.