( ( Sea otters ) ( ( are ( truly ( remarkable ( animals ( to observe ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Sea) (NNS otters)) (VP (VBP are) (ADJP (RB truly) (JJ remarkable) (SBAR (S (NP (NNS animals)) (VP (TO to) (VP (VB observe))))))) (. .)))
Sea otters are truly remarkable animals to observe.
(ROOT (S (NP (NNP Sea) (NNS otters)) (VP (VBP are) (VP (VBN known) (PP (IN for) (S (VP (VBG being) (ADJP (JJ playful) (CC and) (JJ frisky))))))) (. .)))