( ( Cardiac muscle ) ( ( ( makes up ) ( the heart ) ) . ) )
(ROOT (S (NP (NNP Cardiac) (NN muscle)) (VP (VBZ makes) (PRT (RP up)) (NP (DT the) (NN heart))) (. .)))
Cardiac muscle makes up 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))))) (. .)))