( ( the part ) ( of ( ( the brain ) ( that ( controls breathing ) ) ) ) )
(ROOT (NP (NP (DT the) (NN part)) (PP (IN of) (NP (NP (DT the) (NN brain)) (SBAR (WHNP (WDT that)) (S (VP (VBZ controls) (S (VP (VBG breathing))))))))))
the part of the brain that controls breathing
(ROOT (S (NP (DT The) (NN brain) (NN stem)) (VP (VBZ regulates) (NP (NP (DT the) (NN rate)) (PP (IN of) (NP (NN breathing))))) (. .)))