( ( From ( capillaries ( to ( vena cava ) ) ) ) ( , ( ( velocity increases ) ( ( again ( as ( many ( small vessels ) ) ) ) ( ( merge ( to ( ( spill blood ) ( into ( a ( single ( larger vessel ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (PP (IN From) (NP (NP (NNS capillaries)) (PP (TO to) (NP (NN vena) (NN cava))))) (, ,) (NP (NN velocity) (NNS increases)) (ADVP (RB again) (PP (IN as) (NP (JJ many) (JJ small) (NNS vessels)))) (VP (VBP merge) (S (VP (TO to) (VP (VB spill) (NP (NN blood)) (PP (IN into) (NP (DT a) (JJ single) (JJR larger) (NN vessel))))))) (. .)))
From capillaries to vena cava, velocity increases again as many small vessels merge to spill blood into a single larger vessel.
(ROOT (S (NP (NNS Capillaries)) (VP (VBP are) (NP (NP (DT the) (JJS smallest) (NN type)) (PP (IN of) (NP (NN blood) (NNS vessels))))) (. .)))