Complex sentence: Formation occurs during embryogenesis, typically between days 33-41 of gestation, and size of the tumors varies from one to three centimeters in diameter, with the mean being closer to the low end of this range.
Split into simpler sentences: Formation occurs during embryogenesis, typically between days 33 and 41 of gestation. Size of the tumor varies from one to three centimeters in diameter, with the mean being closer to the low end of this range.