( ( ( ( ( ( ( The opening ) ( in ( the back ) ) ) ( is ( the anus ) ) ) , ) and ) ( ( solid waste ) ( ( leaves ( the body ) ) ( through it ) ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (NN opening)) (PP (IN in) (NP (DT the) (NN back)))) (VP (VBZ is) (NP (DT the) (NNS anus)))) (, ,) (CC and) (S (NP (JJ solid) (NN waste)) (VP (VBZ leaves) (NP (DT the) (NN body)) (PP (IN through) (NP (PRP it))))) (. .)))
The opening in the back is the anus, and solid waste leaves the body through it.
(ROOT (S (NP (JJ Solid) (NN waste)) (VP (VBZ is) (VP (VBN eliminated) (PP (IN from) (NP (DT the) (NN body))) (PP (IN through) (NP (DT the) (NNS anus))))) (. .)))