( ( Cardiac muscles ) ( ( are ( ( located only ) ( in ( the heart ) ) ) ) . ) )
(ROOT (S (NP (NNP Cardiac) (NNS muscles)) (VP (VBP are) (VP (VBN located) (ADVP (RB only)) (PP (IN in) (NP (DT the) (NN heart))))) (. .)))
Cardiac muscles are located only in the heart.
(ROOT (S (NP (NNP Cardiac) (NN muscle)) (VP (VBZ makes) (PRT (RP up)) (NP (NP (JJS most)) (PP (IN of) (NP (DT the) (NN heart))))) (. .)))