( ( A mantle ) ( which ( is ( ( a ( ( fold ( in ( the body ) ) ) wall ) ) ( that ( lines ( the shell ) ) ) ) ) ) )
(ROOT (FRAG (NP (NP (DT A) (NN mantle)) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (NP (DT a) (ADJP (JJ fold) (PP (IN in) (NP (DT the) (NN body)))) (NN wall)) (SBAR (IN that) (FRAG (NP (NP (NNS lines)) (NP (DT the) (NN shell))))))))))))
A mantle which is a fold in the body wall that lines the shell
(ROOT (S (NP (NNP Mantle)) (VP (VBZ is) (NP (NP (DT the) (NN layer)) (PP (IN of) (NP (NP (NN tissue)) (PP (IN between) (NP (DT the) (NN body) (CC and) (NN shell))))))) (. .)))