( ( ( Methane production ) ( by ( livestock ( and ( animal waste ) ) ) ) ) ( ( is ( ( a ( major contribution ) ) ( to ( greenhouse ( gas production ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Methane) (NN production)) (PP (IN by) (NP (NN livestock) (CC and) (NN animal) (NN waste)))) (VP (VBZ is) (NP (NP (DT a) (JJ major) (NN contribution)) (PP (TO to) (NP (NN greenhouse) (NN gas) (NN production))))) (. .)))
Methane production by livestock and animal waste is a major contribution to greenhouse gas production.
(ROOT (S (NP (NNS Archaeans)) (VP (VBP produce) (NP (NN methane) (NN gas)) (PP (IN as) (NP (DT a) (NN waste) (NN product)))) (. .)))