( A ( capillary ( blood ( vessel . ) ) ) )
(ROOT (NP (DT A) (JJ capillary) (NN blood) (NN vessel) (. .)))
A capillary blood vessel.
(ROOT (S (NP (NNP Oxygen)) (VP (VBZ is) (VP (VBN transferred) (PP (IN through) (NP (NNS capillaries))))) (. .)))