Q: 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.
 Villous cytotrophoblastic cells were isolated by sequential enzymatic digestion of chorionic villi from the first trimester , second trimester and term placenta and purified on a discontinuous percoll gradient , as described previously . 47 - 49 These cells were positively stained for cytokeratin 7 at 95 % , indicating the cytotrophoblastic origin of the cells .
A:
placenta