( ( ( ( ( Carbon ( is ( ( the ( main element ) ) ( in ( organic compounds ) ) ) ) ) , ) so ) ( carbon ( is ( essential ( to ( life ( on Earth ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Carbon)) (VP (VBZ is) (NP (NP (DT the) (JJ main) (NN element)) (PP (IN in) (NP (JJ organic) (NNS compounds)))))) (, ,) (IN so) (S (NP (NN carbon)) (VP (VBZ is) (ADJP (JJ essential) (PP (TO to) (NP (NP (NN life)) (PP (IN on) (NP (NNP Earth)))))))) (. .)))
Carbon is the main element  in organic compounds, so carbon is essential to life on Earth.
(ROOT (S (NP (NP (NNS Compounds)) (VP (VBG containing) (NP (DT the) (NN element) (NN carbon)))) (VP (VBP are) (NP (NP (DT the) (NN basis)) (PP (IN of) (NP (DT all) (VBN known) (NN life))))) (. .)))
Compounds containing the element carbon are the basis of all known life.