Cells are limited in size by their surface area and volume ratio which means that when cells get so large, there is a limit that they can no longer obtain enough oxygen and nutrients. This process is involved in cell growth.
It is false that a divide separates river systems that travel in the same direction.
After looking at the photograph given above, one sedimentary rock that probably metamorphosed to form rock on unit 6 is called limestone. You can also use the sedimentary rock called dolostone. Both will be acceptable answers to this question.