Complex sentence: Her letter on the conditions of the women in the penal colony asserts that the women have no rights, that the prisoners must work 16--17 hours and sleep 3--4 hours a day, and that they have a day-off every 8th week.
Split into simpler sentences: Her letter on the conditions of the women in the penal colony asserts that the women have no rights. The prisoners must work 16--17 hours and sleep 3--4 hours a day; they have a day-off every 8th week.