The physician identifies a palpable mass in one breast, and the patient is scheduled for a "Lumpectomy." The reason that "Lumpectomy" for breast lumps can be safely performed in some patients is that the breast is divided into multiple lobes, each of which contains a separate duct system with connecting lobules. The normal breast usually contains how many lobes?
2 to 3 5 to 7 10 to 12 15 to 25