( ( As ( they ( are ( social animals ) ) ) ) ( , ( communication ( ( is ( vital ( for them ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN As) (S (NP (PRP they)) (VP (VBP are) (NP (JJ social) (NNS animals))))) (, ,) (NP (NN communication)) (VP (VBZ is) (ADJP (JJ vital) (PP (IN for) (NP (PRP them))))) (. .)))
As they are social animals, communication is vital for them.
(ROOT (S (PP (IN For) (NP (JJ social) (NNS animals))) (, ,) (NP (NN communication)) (VP (VBZ essential)) (. .)))