( ( Case selection ) ( ( was ( ( an ( important factor ) ) ( in ( this research ) ) ) ) . ) )
(ROOT (S (NP (NN Case) (NN selection)) (VP (VBD was) (NP (NP (DT an) (JJ important) (NN factor)) (PP (IN in) (NP (DT this) (NN research))))) (. .)))
Case selection was an important factor in this research.
(ROOT (S (NP (NNP Community) (NNS interactions)) (VP (VBP are) (NP (NP (JJ important) (NNS factors)) (PP (IN in) (NP (JJ natural) (NN selection))))) (. .)))