QUES: From the late 19th century, the South used a colloquial term, the one-drop rule, to classify as black a person of any known African ancestry. This practice of hypodescent was not put into law until the early 20th century. Legally the definition varied from state to state. Racial definition was more flexible in the 18th and 19th centuries before the American Civil War. For instance, President Thomas Jefferson held persons who were legally white (less than 25% black) according to Virginia law at the time, but, because they were born to slave mothers, they were born into slavery, according to the principle of partus sequitur ventrem, which Virginia adopted into law in 1662.

What war changed the way the United States looked at race?
What is the answer?
ANS: the American Civil War
QUES: On December 25, 1991, following the collapse of the Soviet Union, the republic was renamed the Russian Federation, which it remains to this day. This name and "Russia" were specified as the official state names in the April 21, 1992 amendment to the existing constitution and were retained as such in the 1993 Constitution of Russia.

What is the current unofficial name of Russia?
What is the answer?
ANS: unanswerable
QUES: During the Cretaceous, the late Paleozoic-early Mesozoic supercontinent of Pangaea completed its breakup into present day continents, although their positions were substantially different at the time. As the Atlantic Ocean widened, the convergent-margin orogenies that had begun during the Jurassic continued in the North American Cordillera, as the Nevadan orogeny was followed by the Sevier and Laramide orogenies. Though Gondwana was still intact in the beginning of the Cretaceous, Gondwana itself broke up as South America, Antarctica and Australia rifted away from Africa (though India and Madagascar remained attached to each other); thus, the South Atlantic and Indian Oceans were newly formed. Such active rifting lifted great undersea mountain chains along the welts, raising eustatic sea levels worldwide.

What lowered eustatic sea levels?
What is the answer?
ANS:
unanswerable