( ( ( The number ) ( of ( breaths ( taken ( per minute ) ) ) ) ) ( ( is ( the ( respiratory rate ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN number)) (PP (IN of) (NP (NP (NNS breaths)) (VP (VBN taken) (PP (IN per) (NP (NN minute))))))) (VP (VBZ is) (NP (DT the) (JJ respiratory) (NN rate))) (. .)))
The number of breaths taken per minute is the respiratory rate.
(ROOT (S (NP (NP (DT The) (JJ normal) (NN respiratory) (NN rate)) (PP (IN per) (NP (NP (NN minute)) (PP (IN in) (NP (JJ adult) (NNS humans)))))) (VP (VBZ is) (NP (CD 12-18) (NNS breaths))) (. .)))