Teacher: 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.
Teacher: Now, understand the problem? If you are still confused, see the following example:
I have serious allergy in my left eye.
Solution: eye
Reason: Eye is an organ which has been affected, hence should be tagged.

Now, solve this instance:  Our growing understanding of the role that unfavorable patterns of gene expression play in the etiology of neurodegenerative disease emphasizes the need for strategies to selectively block the biosynthesis of harmful proteins in the brain .
Student:
brain