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.

Ex Input:
 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 .

Ex Output:
serum


Ex Input:
 None of the samples collected at necropsy were positive for E . coli O157 .

Ex Output:
samples


Ex Input:
 If the microbial strain was only detected once for a sample , we then checked the second culture results in the suspected infectious sites .

Ex Output:

sample