( That ( ( is ( why ( it ( ( ( does not ) easily ) ( combine ( with ( other elements ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT That)) (VP (VBZ is) (SBAR (WHADVP (WRB why)) (S (NP (PRP it)) (VP (VBZ does) (RB not) (ADVP (RB easily)) (VP (VB combine) (PP (IN with) (NP (JJ other) (NNS elements)))))))) (. .)))
That is why it does not easily combine with other elements.
(ROOT (S (NP (JJ Reactive) (NNS elements)) (VP (VBP are) (ADJP (JJ able) (S (VP (TO to) (VP (VB combine) (ADVP (RBR more) (RB easily)) (PP (IN with) (NP (JJ other) (NNS elements)))))))) (. .)))