Definition: 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:  Second trimester placental tissues were collected at the time of termination of pregnancy at 15 and 25 weeks of gestation ( in weeks of amenorrhea ) in trisomy 21 - affected pregnancies .
Output:
placental