( ( Twin ( to ( twin transfusion ) ) ) ( ( is ( ( a disease ) ( ( in which ) ( ( ( the babies ) ( in ( a ( single placenta ) ) ) ) ( are ( ( connected ( to ( each other ) ) ) ( by ( abnormal ( blood vessels ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Twin)) (PP (TO to) (NP (JJ twin) (NN transfusion)))) (VP (VBZ is) (NP (NP (DT a) (NN disease)) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (NP (NP (DT the) (NNS babies)) (PP (IN in) (NP (DT a) (JJ single) (NN placenta)))) (VP (VBP are) (VP (VBN connected) (PP (TO to) (NP (DT each) (JJ other))) (PP (IN by) (NP (JJ abnormal) (NN blood) (NNS vessels))))))))) (. .)))
Twin to twin transfusion is a disease in which the babies in a single placenta are connected to each other by abnormal blood vessels.
(ROOT (S (NP (NP (DT A) (NN connection)) (PP (TO to) (NP (DT the) (NN placenta)))) (VP (VBZ is) (VP (VBN required) (PP (IN for) (NP (DT a) (JJ newborn) (NN baby))) (S (VP (TO to) (VP (VB begin) (NP (NN breathing))))))) (. .)))