( MASS ( ( EXTINCTIONS ( ( A ( mass extinction ) ) ( is ( ( a ( ( relatively sudden ) ( , ( global decrease ) ) ) ) ( in ( ( the diversity ) ( of ( life forms ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS MASS)) (VP (VBZ EXTINCTIONS) (SBAR (S (NP (DT A) (JJ mass) (NN extinction)) (VP (VBZ is) (NP (NP (DT a) (ADJP (RB relatively) (JJ sudden)) (, ,) (JJ global) (NN decrease)) (PP (IN in) (NP (NP (DT the) (NN diversity)) (PP (IN of) (NP (NN life) (NNS forms)))))))))) (. .)))
MASS EXTINCTIONS A mass extinction is a relatively sudden, global decrease in the diversity of life forms.
(ROOT (S (NP (NP (ADJP (JJ Sudden) (CC and) (JJ dramatic)) (NNS losses)) (PP (IN of) (NP (NN biodiversity)))) (VP (VBP are) (VP (VBN called) (NP (JJ mass) (NN extinction)))) (. .)))