(S (S (BASENP (NNS Scientists)) (VP (VBP say) (SBAR (SBAR (IN that) (S (NP (BASENP (DT the) (NN heat) (NN source)) (VP (VBG producing) (BASENP (DT the) (NNS geysers)))) (VP (VBZ is) (QT (DQL ``) (ADJP (JJ organic)) (DQR ''))))) (CC and) (SBAR (IN that) (S (NP (BASENP (DT the) (NN material)) (VP (VBN used) (S (VP (TO to) (VP (VB spew) (BASENP (PRP them))))))) (VP (VBZ is) (VP (VBN caused) (PP (IN by) (NP (BASENP (DT the) (NN decaying)) (PP (IN of) (NP (BASENP (JJ radioactive) (NN material)) (PP (IN from) (PP (IN inside) (BASENP (DT the) (NN moon))))))))))))))) (PERIOD .))