Instructions: 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.
Input:  RT - PCR analysis revealed constitutive expression of the SLAP - 2 gene in bone marrow macrophages .
Output:
bone