( ( ( ( ( ( Most ( mollusk species ) ) ( only ( live ( in ( the ocean ) ) ) ) ) , ) but ) ( some ( live ( ( ( in freshwater ) or ) ( on land ) ) ) ) ) . )
(ROOT (S (S (NP (JJS Most) (NN mollusk) (NNS species)) (ADVP (RB only)) (VP (VBP live) (PP (IN in) (NP (DT the) (NN ocean))))) (, ,) (CC but) (S (NP (DT some)) (VP (VBP live) (PP (PP (IN in) (NP (NN freshwater))) (CC or) (PP (IN on) (NP (NN land)))))) (. .)))
Most mollusk species only live in the ocean, but some live in freshwater or on land.
(ROOT (S (NP (RBS Most) (JJ red) (NN algae) (NNS species)) (VP (VBP live) (PP (IN in) (NP (NNS oceans)))) (. .)))