These are in turn surrounded and supported by holders of school certificates and other qualifications.
( These ( ( are ( in ( turn ( ( ( surrounded and ) supported ) ( by ( holders ( of ( ( ( school certificates ) and ) ( other qualifications ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT These)) (VP (VBP are) (PP (IN in) (NP (NP (NN turn)) (VP (VBN surrounded) (CC and) (VBN supported) (PP (IN by) (NP (NP (NNS holders)) (PP (IN of) (NP (NP (NN school) (NNS certificates)) (CC and) (NP (JJ other) (NNS qualifications)))))))))) (. .)))
These have no support and operate in isolation.
( These ( ( ( ( have ( no support ) ) and ) ( operate ( in isolation ) ) ) . ) )
(ROOT (S (NP (DT These)) (VP (VP (VBP have) (NP (DT no) (NN support))) (CC and) (VP (VBP operate) (PP (IN in) (NP (NN isolation))))) (. .)))