3. What is the probability that a random mutation will occur in any given gene?

The answer is lymph sinuses.

Sorry  i don't understand can you rephrase that

To determine whether gestational trophoblastic disease is presentgestational trophoblastic disease is abnormal proliferation and then degeneration of the trophoblastic villi. the embryo fails to develop beyond a primitive start. abnormal trophoblast cells must be identified because they are associated with choriocarcinoma, a rapidly metastasizing malignancy. this is why it is important for any woman who begins to miscarry at home to bring any clots or tissue passed to the hospital with her. the presence of clear fluid-filled cysts changes the diagnosis from a simple miscarriage to gestational trophoblastic disease. the client is not instructed to bring in passed tissue to determine whether infection is present or the fetus is viable or to determine the stage of development of the fetus.