( This ( ( allows ( ( ( ( ( compressed ( lung tissue ) ) ( to ( re-expand ( ( so less ) air ) ) ) ) ( is trapped ) ) and ) ( ( ( ( ( high ( negative pressures ) ) , ) ( which ( cause ( ( the airways ) ( to collapse ) ) ) ) ) , ) ( can ( be reduced ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ allows) (SBAR (S (S (NP (NP (JJ compressed) (NN lung) (NN tissue)) (PP (TO to) (NP (JJ re-expand) (ADJP (RB so) (JJR less)) (NN air)))) (VP (VBZ is) (ADJP (JJ trapped)))) (CC and) (S (NP (NP (JJ high) (JJ negative) (NNS pressures)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBP cause) (S (NP (DT the) (NNS airways)) (VP (TO to) (VP (VB collapse))))))) (, ,)) (VP (MD can) (VP (VB be) (VP (VBN reduced)))))))) (. .)))
This allows compressed lung tissue to re-expand so less air is trapped and high negative pressures, which cause the airways to collapse, can be reduced.
(ROOT (S (SBAR (IN As) (S (NP (DT a) (NN diver)) (VP (VBZ descends)))) (, ,) (NP (NP (DT the) (NN increase)) (PP (IN in) (NP (NN pressure)))) (VP (VBZ causes) (NP (NP (DT the) (NN body) (POS 's)) (NN air) (NNS pockets)) (PP (IN in) (NP (NP (DT the) (NNS ears) (CC and) (NNS lungs)) (PP (TO to) (NP (NNS compress)))))) (. .)))