( ( ( This ( reduced level ) ) ( of ( carbon dioxide ) ) ) ( ( causes ( ( ( the arteries ) , ) ( ( including ( ( the ( carotid artery ) ) ( ( ( going ( to ( the brain ) ) ) , ) ( to constrict ) ) ) ) ( , ( thus ( ( reducing ( ( the flow ) ( of blood ) ) ) ( throughout ( the body ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT This) (VBN reduced) (NN level)) (PP (IN of) (NP (NN carbon) (NN dioxide)))) (VP (VBZ causes) (NP (NP (DT the) (NNS arteries)) (, ,) (UCP (PP (VBG including) (NP (NP (DT the) (JJ carotid) (NN artery)) (VP (VBG going) (PP (TO to) (NP (DT the) (NN brain))) (, ,) (S (VP (TO to) (VP (VB constrict))))))) (, ,) (S (ADVP (RB thus)) (VP (VBG reducing) (NP (NP (DT the) (NN flow)) (PP (IN of) (NP (NN blood)))) (PP (IN throughout) (NP (DT the) (NN body)))))))) (. .)))
This reduced level of carbon dioxide causes the arteries, including the carotid artery going to the brain, to constrict, thus reducing the flow of blood throughout the body.
(ROOT (S (NP (DT The) (NN brain)) (VP (VBP stem) (S (NP (NP (NN monitor)) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-))) (NP (NP (DT the) (NN level)) (PP (IN of) (NP (NP (NN carbon) (NN dioxide)) (PP (IN in) (NP (DT the) (NN blood)))))))) (. .)))