In this task, you are given a sentence. You are expected to write the name of the organism substances in the body mentioned in the input. Although there might be several correct answers, you need to write one of them.

Q:  Residential proximity to the plant and younger age ( up to 13 years old ) were the strongest predictors of an individual ' s serum 2 , 3 , 7 , 8 - TCDD level .

A: serum
****
Q:  To investigate the potential role of sympathetic nerves in preventing pronounced increases in cerebral blood flow , we evaluated the effects of abrupt hypertension on the cerebral circulation of newborn pigs with intact cerebral sympathetic innervation and after cerebral sympathetic denervation .

A: blood
****
Q:  Absence of correlations to TBSA % , FTB % , blood transfusion , opiates provided , and multiple organ failure score and laboratory infection variables together with the finding that decreased oxidative burst was uniform after the injury , suggesting that this immunosuppression is primarily due to the general metabolic response rather than recurring infections .

A:
blood
****