What nation possessed the Crimea before Russia invaded it?

What is the "great pacific garbage patch"? (a) a large area of marine debris concentrated by rotating ocean currents (b) a large area around the pacific rim where debris collects from natural disasters such as tsunamis (c) an area in the pacific ocean where trash is intentionally dumped due to lack of landfill availability (d) a large trash dump located in hawaii

The mantle is made up of which structural zones?

Political boundaries are determined by the political party in control at the time. true or false