Why countries strive hard to acquire the status of a nation-state ?

The continents of africa and south america used to "fit together” like puzzle pieces. about how far back in time would you have to go to find the formation of the atlantic ocean? 600 million years 430 million years 200 million years 90 million years

Think about the different ecosystems we would find while studying the physical geography of the united states. which ecosystem do you live in? in a short paragraph, describe the ecosystem that surrounds you. what kinds of plants and animals are common in your area?

Who is the current chief justice of the united states?