Simplify the following text for a Grade 10 native English-speaking person.
Original: Some species of coral-reef sea cucumbers within the order Aspidochirotida can defend themselves by expelling their sticky cuvierian tubules ( enlargements of the respiratory tree that float freely in the coelom ) to entangle potential predators .
Simplified: Some species of coral reef sea cucumbers defend themselves by expelling sticky cuvierian tubules to entangle potential predators . These tubules are attached to the respiratory tree in the gut .