Im not very sure but I think its lipid
1) At the bottom of the trench, the Romans put a layer of big stones. 2) Broken stones, pebbles,3) cement and sand to make a firm base. 4) Paving stones formed the surface of the road. These were cut so they fitted together tightly.
The Khmer Rouge assumed leadership in A. Cambodia.
The answer is A. Aus & Nz became separated.