2,3, 1, 6 that the answer
In 1865 and 1866, after the civil war. I'm not sure who wrote them
Judicial Review - The power of the Supreme Court to declare laws unconstitutional is not in the constitution yet it has become one of the basic tenants of the checks and balances system. ... As an example of how important the unwritten constitution has become one might cite the example of the two term limit.
They got to know with the photographs from the U - 2 spy plane.
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Heres your answer!!hope this is helpful