Both unions established a foothold in the industry because they represented strategic workers in the apparel production  the skilled cutter working inside manufacturers' plants.
( ( Both unions ) ( ( ( ( established ( a foothold ) ) ( in ( the industry ) ) ) ( because ( they ( represented ( ( ( strategic workers ) ( in ( the ( apparel production ) ) ) ) ( ( the ( skilled cutter ) ) ( working ( inside ( ( manufacturers ' ) plants ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT Both) (NNS unions)) (VP (VBD established) (NP (DT a) (NN foothold)) (PP (IN in) (NP (DT the) (NN industry))) (SBAR (IN because) (S (NP (PRP they)) (VP (VBD represented) (S (NP (NP (JJ strategic) (NNS workers)) (PP (IN in) (NP (DT the) (NN apparel) (NN production)))) (NP (NP (DT the) (JJ skilled) (NN cutter)) (VP (VBG working) (PP (IN inside) (NP (NP (NNS manufacturers) (POS ')) (NNS plants)))))))))) (. .)))
Strategic workers were represented by the unions, which gave them a foothold in the industry.
( ( Strategic workers ) ( ( were ( represented ( by ( ( ( the unions ) , ) ( which ( ( gave them ) ( ( a foothold ) ( in ( the industry ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Strategic) (NNS workers)) (VP (VBD were) (VP (VBN represented) (PP (IN by) (NP (NP (DT the) (NNS unions)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBD gave) (NP (PRP them)) (NP (NP (DT a) (NN foothold)) (PP (IN in) (NP (DT the) (NN industry))))))))))) (. .)))