Which condition must be true for a nation to exist?

Which best describes why it is necessary to evaluate a solution?

When discussing comparative and absolute advantage, which best describes specialization? developing expertise in certain types of production limiting the types of goods and services produced targeting specific consumers and retailers producing certain items for specific market segments the answer is: the act of limiting the kinds of goods and services produced

What was different about warfare in the early 1800s and early 1900s?