True
ptolemaic system
True
yes
yes
Ptolemaic system
The word concentrically simply means in a concentric manner. Concentric is a term used to describe spheres of different sizes with a common middle point.
AAristotle developed the theory that planets are spheres and move in concentric circles around the sun
Eudoxus
density stratification
The Earth's mantle is below the crust. The layers of the Earth form concentric spheres. Below the mantle is the core.
The difference between a stone keep castle and a concentric castle is that a stone keep castle had hardly any defence. The only defence was their high walls. But the concentric castles had loads of walls surounding them. The word 'concentric' actually means with common middle point: describes circles and spheres of different sizes with the same middle point.