The Indo-European culture language, while the Greeks got most of their culture from Egypt and Mesopotamia. With a little Sparta in there.
The correct answer is:
An understanding of the number and size of leftover planetesimals in the early solar system.
The giant-impact hypothesis proposes that the Moon was created out of what was left of a collision between Earth and an astronomical body the size of Mars, around 4.5 billion years ago, in the Hadean eon. The heavy bombardment was a period when leftover planetesimals hit planets during the solar system's first hundred million years.
The United States presidential election of 1876 was one of the most disputed presidential elections in American history. Samuel J. Tilden of New York outpolled Ohio's Rutherford B. Hayes in the popular vote, and had 184 electoral votes to Hayes' 165, with 20 votes uncounted.
