( ( Capillaries ( The ( tiniest ( blood vessels ) ) ) ) . )
(ROOT (NP (NP (NNS Capillaries)) (NP (DT The) (JJS tiniest) (NN blood) (NNS vessels)) (. .)))
Capillaries The tiniest blood vessels.
(ROOT (S (NP (NNP Oxygen)) (VP (VBZ is) (VP (VBN transferred) (PP (IN through) (NP (NNS capillaries))))) (. .)))