Air pollution in us national parks is effecting the environment in what way(s)?

Which of the following best describes the circumstance under which countries block the importation of certain products into their country? a. importation blockade b.trade barrier c.trade inhibitor d. domestic protection act

What is the thickest layer of earth called?

Plz answer ! find the alps. what countries and country borders intersect this major mountain range? which borders seem to be defined by the edges of the mountains? which borders seem to be defined by the edges of the mountains? which borders cut across the mountains?