All of them were river valley based civilization remains, thought we have many cities we have many cities in uneven terrains and arid regions , which may either have been outposts for trade, or were well used with water harvesting techniques to use the little available water through the rains . Created artifacts indentify as “art”, religion and priestly class that maintained rituals and douctrines
<span>Similar to how sand sinks to the bottom of a river, during the formation of the planet, when earth was still a hot ball of liquid rock and minerals; the most dense materials would make their way to the bottom, while less dense materials (like liquid rock) would "float" on the top of this growing ball of liquid metal. As iron was (and is) plentiful, and quite a dense mineral (which is why it blocks x-rays), it makes up the majority of the Earth's core. So I would say A.</span>
Give them food and supplies
You’ll have to be specific. Well first off it’s a country in the Balkans. It really doesn’t have access to the water except by a very small corridor. But it is also a Republic