( Autotrophs ( ( may ( be ( ( photoautotrophs or ) chemoautotrophs ) ) ) . ) )
(ROOT (S (NP (NNS Autotrophs)) (VP (MD may) (VP (VB be) (NP (NNS photoautotrophs) (CC or) (NNS chemoautotrophs)))) (. .)))
Autotrophs may be photoautotrophs or chemoautotrophs .
(ROOT (S (NP (NNS Photoautotrophs) (CC and) (NNS chemoautotrophs)) (VP (VBP are) (NP (NP (CD two) (JJ basic) (NNS types)) (PP (IN of) (NP (NNS autotrophs))))) (. .)))