( Sunlight ( ( provides ( ( the energy ) ( that ( ( drives ( ( nearly all ) ecosystems ) ) ( although ( ( only ( photosynthetic organisms ) ) ( use ( it ( directly ( as ( an ( energy source ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Sunlight)) (VP (VBZ provides) (NP (NP (DT the) (NN energy)) (SBAR (WHNP (WDT that)) (S (VP (VBZ drives) (NP (QP (RB nearly) (DT all)) (NNS ecosystems)) (SBAR (IN although) (S (NP (RB only) (JJ photosynthetic) (NNS organisms)) (VP (VBP use) (S (NP (PRP it)) (ADJP (RB directly) (PP (IN as) (NP (DT an) (NN energy) (NN source))))))))))))) (. .)))
Sunlight provides the energy that drives nearly all ecosystems although only photosynthetic organisms use it directly as an energy source.
(ROOT (S (NP (NNP Sunlight)) (VP (VBZ is) (NP (NP (DT the) (JJ main) (NN source)) (PP (IN of) (NP (NP (NN energy)) (PP (IN for) (NP (NP (DT all)) (PP (IN of) (NP (NP (DT the) (NNS organisms)) (PP (IN in) (NP (JJS most) (NN food) (NNS chains))))))))))) (. .)))
Sunlight is the main source of energy for all of the organisms in most food chains.