what allows it to rank with its worthy predecessors 
(ROOT (SBAR (WHNP (WP what)) (S (VP (VBZ allows) (S (NP (PRP it)) (VP (TO to) (VP (VB rank) (PP (IN with) (NP (PRP$ its) (JJ worthy) (NNS predecessors))))))))))
(ROOT (SBAR (WHNP (WP )) (S (VP (VBZ ) (S (NP (PRP )) (VP (TO ) (VP (VB ) (PP (IN ) (NP (PRP$ ) (JJ ) (NNS ))))))))))