( ( ( ( ( Backbone ( since ( ( all rooms ) ( can ( be ( reached ( from ( ( the ( main ( wiring closet ) ) ) ( within ( the ( 90 ( meter ( length limitation ) ) ) ) ) ) ) ) ) ) ) ) ) ( there ( is ( no ( need ( to ( have ( ( more ( than one ) ) ( wiring closet ) ) ) ) ) ) ) ) ) and ) ( this ( eliminates ( ( the need ) ( for ( a ( backbone network ) ) ) ) ) ) ) . )
(ROOT (S (S (SBAR (ADVP (RB Backbone)) (IN since) (S (NP (DT all) (NNS rooms)) (VP (MD can) (VP (VB be) (VP (VBN reached) (PP (IN from) (NP (NP (DT the) (JJ main) (NN wiring) (NN closet)) (PP (IN within) (NP (DT the) (CD 90) (NN meter) (NN length) (NN limitation)))))))))) (NP (EX there)) (VP (VBZ is) (NP (DT no) (NN need) (S (VP (TO to) (VP (VB have) (NP (QP (JJR more) (IN than) (CD one)) (NN wiring) (NN closet)))))))) (CC and) (S (NP (DT this)) (VP (VBZ eliminates) (NP (NP (DT the) (NN need)) (PP (IN for) (NP (DT a) (NN backbone) (NN network)))))) (. .)))
Backbone since all rooms can be reached from the main wiring closet within the 90 meter length limitation there is no need to have more than one wiring closet and this eliminates the need for a backbone network.
(ROOT (S (NP (NP (CD One)) (PP (IN of) (NP (NP (DT the) (JJ main) (NNS features)) (SBAR (S (NP (DT all) (NNS vetebrates)) (VP (VBP have) (VP (PP (IN in) (NP (JJ common)))))))))) (VP (VBZ is) (NP (DT a) (NN backbone))) (. .)))