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:  Among adolescent boys in Chapaevsk , Russia , higher serum levels of sum of dioxin - like compounds and sum of dioxin TEQs were positively associated with increased age , consumption of fish , local meats other than chicken , and inversely with weeks of gestation .

A: serum
****
Q:  There was no association between the distance of the residence from the Khimprom plant during the pregnancy and subsequent serum dioxin levels .

A: serum
****
Q:  In a 1 . 5 ml microcentrifuge tube , plasmid ( 1 microg / microl ) and siRNA were mixed with growth medium without fetal calf serum ( FCS ) , 0 . 5 microl 1 . 5 M sucrose and 3 microl X - tremeGENE per microgram nucleic acid to a final volume of 22 . 5 microl .

A:
serum
****