How do you distinguish one period from the next?

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

How have citizens in aralsk adapted to the changes brought about by the shrinking of the sea?

Suppose that the sun shrank in size but that its mass remained the same. what would happen to the orbit of the earth?