( ( ( Beta particles ) ( are ( less penetrating ) ) ) ( , ( they ( ( ( ( ( can ( travel ( through ( ( ( ( ( several meters ) ( of air ) ) , ) ( but not ) ) walls ) ) ) ) , ) and ) ( can ( ( cause ( serious injury ) ) ( to ( organisms ( that ( are ( near ( to ( the source ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (NP (NN Beta) (NNS particles)) (VP (VBP are) (ADJP (RBR less) (JJ penetrating)))) (, ,) (NP (PRP they)) (VP (VP (MD can) (VP (VB travel) (PP (IN through) (NP (NP (NP (JJ several) (NNS meters)) (PP (IN of) (NP (NN air)))) (, ,) (CONJP (CC but) (RB not)) (NP (NNS walls)))))) (, ,) (CC and) (VP (MD can) (VP (VB cause) (NP (JJ serious) (NN injury)) (PP (TO to) (NP (NP (NNS organisms)) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (ADJP (JJ near) (PP (TO to) (NP (DT the) (NN source)))))))))))) (. .)))
Beta particles are less penetrating, they can travel through several meters of air, but not walls, and can cause serious injury to organisms that are near to the source.
(ROOT (S (NP (JJ Meter) (JJ much) (NN distance)) (VP (MD can) (VP (VB beta) (NP (JJ particles) (NN travel)) (PP (IN through) (NP (NN air))))) (. .)))