What is the best kind of boundary between states (countries)

The roman empire fell around the 5th century, and as islam spread in the 7th century, trade between europe and china slowed. chinese traders were blocked from westward expansion into europe when the chinese army was defeated by muslim fighters in the area known as syr darya. the trade routes, known as the silk road, fell into disuse, and trade between the far east and europe nearly stopped. it wasn't until the 13th century when the mongols invaded and controlled central asia and large parts of the middle east that extensive trade along these routes was opened again. based upon the paragraph above and your knowledge of the mongols, which of the following statements is correct? a. the mongols unified regions along the silk road, allowing for safe transport of goods. b. muslims controlled busy trade routes into china from the 5th to the 7th centuries. c. without access to european markets, the chinese were unable to obtain raw materials. d. the mongols replaced the roman empire as the dominant force in western europe.

Read this scenario: a group of immigrant farmworkers forms an interest group to argue for workers' rights in their state. they cannot afford an experienced lobbyist, however, and are unable to secure meetings with important lawmakers. which negative aspect of interest groups does the scenario illustrate? a. lacking power without funding b. supporting candidates who may not be the best choice for a position c. focusing only on group members' goals d. resorting to unethical tactics

The flashing of directional signals as it indicates that used it safe to bed