( It ( ( ( is ( for ( this reason ) ) ) ( that ( biologists ( refer ( to ( autotrophs ( as ( ( the producers ) ( of ( the biosphere ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (PP (IN for) (NP (DT this) (NN reason))) (SBAR (IN that) (S (NP (NNS biologists)) (VP (VBP refer) (S (VP (TO to) (VP (VB autotrophs) (PP (IN as) (NP (NP (DT the) (NNS producers)) (PP (IN of) (NP (DT the) (NN biosphere)))))))))))) (. .)))
It is                for this reason that biologists refer to autotrophs as the producers                of the biosphere.
(ROOT (S (NP (NNS Autotrophs)) (VP (VBZ is) (NP (NP (DT another) (NN name)) (PP (IN for) (NP (NNS producers))))) (. .)))