( ( ( Blood supply ) ( to brain ) ) ( ( ( is mainly ) ( via ( the ( internal ( carotid artery ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NN Blood) (NN supply)) (PP (TO to) (NP (NN brain)))) (VP (VBZ is) (ADVP (RB mainly)) (PP (IN via) (NP (DT the) (JJ internal) (JJ carotid) (NN artery)))) (. .)))
Blood supply       to brain is mainly via the internal carotid artery .
(ROOT (S (NP (DT The) (JJ carotid) (NN artery)) (VP (VBZ takes) (NP (NN blood)) (PP (TO to) (NP (DT the) (NN brain)))) (. .)))
The carotid artery takes blood to the brain.