What were the immediate conflicts and deeper causes that led the united states and the soviet union to go from being allies to bitter cold war rivals?

The two countries changed from being neutral toward each other to being rivals.

Explanation:

early human migrations are the earliest migrations and expansions of archaic and modern humans across continents and are believed to have begun approximately 2 million years ago with the out of africa migration of homo erectus. this initial migration was followed by other archaic humans including h. heidelbergensis, which lived around 500,000 years ago and was the likely ancestor of both denisovans and neanderthals. early hominids were said to have "crossed land bridges that were eventually covered in water" .

within africa, homo sapiens dispersed around the time of its speciation, roughly 300,000 years ago.the "recent african origin" paradigm suggests that the anatomically modern humans outside of africa descend from a population of homo sapiens migrating from east africa roughly 70,000 years ago and spreading along the southern coast of asia and to oceania before 50,000 years ago. modern humans spread across europe about 40,000 years ago.

the migrating modern human populations are known to have interbred with local varieties of archaic humans, so that contemporary human populations are descended in small part (below 10% contribution) from regional varieties of archaic humans.

after the last glacial maximum, north eurasian populations migrated to the americas about 20,000 years ago. northern eurasia was peopled after 12,000 years ago, in the beginning holocene. arctic canada and greenland were reached by the paleo-eskimo expansion around 4,000 years ago. finally, polynesia was peopled after 2,000 years ago, by the austronesian expansion.

(1) university of virginia: its a colonial heritage was founded in 1819 by declaration of independence author and former president thomas -charlottesville, virginia, united

(2) yellowstone national park is an american national park located in wyoming,montana and idaho and is a colonial heritage site.it was established by us congress and signed into law by president ulysses g grant on march 1,1872.yellowstone is usa's and world's first national park and a heritage site.the park is also known for its wildlife and its geothermal geysers.

(3) yosemite national park: : : colonial heritage site in north in western sierra nevada of central was designated a world heritage site in 1984..it is famous for its granite cliffs,waterfalls,clear streams,giant sequoia groves,lakes,mountains,glaciers and biological

(4) grand canyon national park: : colonial heritage site in north in north western arizona and is 15th site declared as national park..the park's central feature is the grand canyon, a gorge of the colorado river,which is also considered one of the wonders of the world.the park covers 1217262 acres.the grand canyon was designated a world heritage site in by unesco in 1979.

(5) taos pueblo

(6) redwood national park

(7) cahokia mounds

(8) wrangell-st. elias national park

(9) glacier bay national park

(10) kluane national park

(11) tatshenshini-alsek provincial park

(12) mammoth cave national park

(13) olympic national park

(14) great smoky mountains national park

(15) quebec city

(16) everglades national park

(17) lunenburg, nova scotia

(18) glacier national park

(19)chichen itza