( ( ( Solar , ) ( ( wind , ) ( hydroelectric ( , ( geothermal ( and ( biomass ( electricity generation ) ) ) ) ) ) ) ) ( ( are ( example ( of ( renewable ( energy sources ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Solar)) (, ,) (NP (NP (NN wind)) (, ,) (NP (JJ hydroelectric) (, ,) (NN geothermal) (CC and) (NNS biomass) (NN electricity) (NN generation)))) (VP (VBP are) (NP (NP (NN example)) (PP (IN of) (NP (JJ renewable) (NN energy) (NNS sources))))) (. .)))
Solar, wind, hydroelectric, geothermal and biomass electricity generation are example of renewable energy sources.
(ROOT (S (NP (NNS Biomass)) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (DT a) (JJ renewable) (NN energy) (NN resource))))) (. .)))
Biomass is an example of a renewable energy resource.