Many scientists believe that the first Paleo-Indians in North America a. arrived between 30,000 and 13,000 years ago
b. became extinct because the climate got too cold.
c. built boats to sail along the coast and trade with North America.
d. used the land bridge between Asia and North America to facilitate trade

Where did the term “iron curtain” originate? the warsaw pact used the term iron curtain as a code word for communism. in a 1946 speech, british prime minister winston churchill said an iron curtain had fallen across the continent of europe. while visiting western europe in 1946, u.s. president harry truman commented that the mountains there looked like iron curtains. russian general secretary joseph stalin instructed citizens of eastern europe to hang iron curtains over their windows to protect themselves from stray bullets.