Question: With the defeat of the Confederacy in 1865, the Reconstruction Era began. The United States abolished slavery without compensation to slaveholders or reparations to freedmen. A Republican Party coalition of black freedmen, northern carpetbaggers and local scalawags controlled state government for three years. The white conservative Democrats regained control of the state legislature in 1870, in part by Ku Klux Klan violence and terrorism at the polls, to suppress black voting. Republicans were elected to the governorship until 1876, when the Red Shirts, a paramilitary organization that arose in 1874 and was allied with the Democratic Party, helped suppress black voting. More than 150 black Americans were murdered in electoral violence in 1876.
Is there an answer to this question: When did white Democrats regain control of the state legislature?

Answer: 1870

Question: In 1671, Robert Boyle discovered and described the reaction between iron filings and dilute acids, which results in the production of hydrogen gas. In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "flammable air". He speculated that "flammable air" was in fact identical to the hypothetical substance called "phlogiston" and further finding in 1781 that the gas produces water when burned. He is usually given credit for its discovery as an element. In 1783, Antoine Lavoisier gave the element the name hydrogen (from the Greek - hydro meaning "water" and - genes meaning "creator") when he and Laplace reproduced Cavendish's finding that water is produced when hydrogen is burned.
Is there an answer to this question: Who discovered Hydrogen gas?

Answer: Robert Boyle

Question: Early progress toward the development of vaccines occurred throughout this period, primarily in the form of academic and government-funded basic research directed toward the identification of the pathogens responsible for common communicable diseases. In 1885 Louis Pasteur and Pierre Paul Emile Roux created the first rabies vaccine. The first diphtheria vaccines were produced in 1914 from a mixture of diphtheria toxin and antitoxin (produced from the serum of an inoculated animal), but the safety of the inoculation was marginal and it was not widely used. The United States recorded 206,000 cases of diphtheria in 1921 resulting in 15,520 deaths. In 1923 parallel efforts by Gaston Ramon at the Pasteur Institute and Alexander Glenny at the Wellcome Research Laboratories (later part of GlaxoSmithKline) led to the discovery that a safer vaccine could be produced by treating diphtheria toxin with formaldehyde. In 1944, Maurice Hilleman of Squibb Pharmaceuticals developed the first vaccine against Japanese encephelitis. Hilleman would later move to Merck where he would play a key role in the development of vaccines against measles, mumps, chickenpox, rubella, hepatitis A, hepatitis B, and meningitis.
Is there an answer to this question: What compound made the diphtheria vaccine safer to use?

Answer: formaldehyde

Question: The term "great power" was first used to represent the most important powers in Europe during the post-Napoleonic era. The "Great Powers" constituted the "Concert of Europe" and claimed the right to joint enforcement of the postwar treaties. The formalization of the division between small powers and great powers came about with the signing of the Treaty of Chaumont in 1814. Since then, the international balance of power has shifted numerous times, most dramatically during World War I and World War II. While some nations are widely considered to be great powers, there is no definitive list of them. In literature, alternative terms for great power are often world power or major power, but these terms can also be interchangeable with superpower.
Is there an answer to this question: During the post Napoleonic era where were the first Great Powers concentrated?

Answer:
Europe