In this task, you will be given sentences in which your task is to recognize the name of the organ of the body. An organ is a collection of tissues that structurally form a functional unit specialized to perform a particular function. Although there might be several correct answers, you need to write one of them.
One example is below.
Q: I have serious allergy in my left eye.
A: eye
Rationale: Eye is an organ which has been affected, hence should be tagged.
Q:  In summary , defense mechanisms against oxidative stress in the brain differ with age .
A:
brain