( ( ( ( ( ( A ( bubble ring ) ) , ) or ) ( toroidal bubble ) ) , ) ( ( is ( ( an ( underwater ( vortex ring ) ) ) ( where ( ( an ( air bubble ) ) ( ( ( occupies ( ( the core ) ( of ( the vortex ) ) ) ) , ) ( forming ( a ( ring shape ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NN bubble) (NN ring)) (, ,) (CC or) (NP (JJ toroidal) (NN bubble)) (, ,)) (VP (VBZ is) (NP (NP (DT an) (JJ underwater) (NN vortex) (NN ring)) (SBAR (WHADVP (WRB where)) (S (NP (DT an) (NN air) (NN bubble)) (VP (VBZ occupies) (NP (NP (DT the) (NN core)) (PP (IN of) (NP (DT the) (NN vortex)))) (, ,) (S (VP (VBG forming) (NP (DT a) (NN ring) (NN shape))))))))) (. .)))
A bubble ring, or toroidal bubble, is an underwater vortex ring where an air bubble occupies the core of the vortex, forming a ring shape.
(ROOT (S (NP (DT An) (JJ underwater) (NN spider)) (VP (VBZ uses) (NP (JJ shiny) (NN air) (NN bubble) (S (VP (TO to) (VP (VP (VB breathe)) (CC and) (VP (VB keep) (ADJP (JJ alive)))))))) (. .)))