( ( This sac ) ( ( contains ( ( ( ( ( the ( spinal cord ) ) and ) ( the meninges ) ) , ) ( ( ( the ( protective layers ) ) ( of tissue ) ) ( that ( enclose ( the ( spinal cord ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN sac)) (VP (VBZ contains) (NP (NP (NP (DT the) (JJ spinal) (NN cord)) (CC and) (NP (DT the) (NNS meninges))) (, ,) (NP (NP (DT the) (JJ protective) (NNS layers)) (PP (IN of) (NP (NN tissue))) (SBAR (WHNP (WDT that)) (S (VP (VB enclose) (NP (DT the) (JJ spinal) (NN cord)))))))) (. .)))
This sac contains the spinal cord and the meninges, the protective layers of tissue that enclose the spinal cord.
(ROOT (S (NP (NP (DT The) (CD three) (NNS layers)) (PP (IN of) (NP (NP (JJ protective) (NNS coverings)) (PP (IN of) (NP (DT the) (JJ spinal) (NN cord)))))) (VP (VBZ is) (VP (VBN called) (NP (DT the) (NNS meninges)))) (. .)))