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.
1941 and 1945, across German-occupied Europe, Nazi Germany and its collaborators systematically murdered some six million Jews, around two-thirds of Europe's Jewish population.[a][c] The murders were carried out in pogroms and mass shootings; by a policy of extermination through work in concentration camps; and in gas chambers and gas vans in German extermination camps, chiefly Auschwitz, Bełżec, Chełmno, Majdanek, Sobibór, and Treblinka in occupied Poland
It's between b or c. Im leaning towards c. 16th & 17th century was the renaissance and reformation.
Aristotle believed human nature was a superior to other beings on the planet because of how much further humans have come, the intelligence level of humans, and all we have done.