Inventors and Scientific Discoveries

Waldemar Haffkine invented plague vaccine in India.

Carl P. Swanson is known as father of modern cytology.

Karl Landsteiner and Erwin Popper discovered poliovirus in 1908 by proving that it was not a bacterium that caused paralysis, but a much smaller entity - a virus.

John Napier, a Scottish mathematician, invented logarithms in 1614, revolutionizing calculations. Leibniz developed calculus, Fibonacci introduced the Fibonacci sequence, and Euclid founded geometry.

Albert Michelson was indeed the first American to win a Nobel Prize in Physics (1907) for his precise measurements of the speed of light using the Michelson-Morley experiment apparatus. He was born in Prussia (now Poland) and emigrated to the US as a child. Max Planck was German, Einstein was also German-born, and Thomas Young was British.

Alessandro Volta invented the first electric cell (the voltaic pile) in 1800, proving electricity could be generated chemically. The volt unit is named after him. Fermi worked on nuclear reactors, Graham Bell invented the telephone, and Faraday discovered electromagnetic induction.

Ernest Rutherford discovered the nuclear structure of the atom through his gold foil experiment, showing that positive charge and mass are concentrated in a tiny nucleus. Niels Bohr developed the atomic model, J.J. Thomson discovered the electron, and Chadwick discovered the neutron.

Henri Becquerel discovered natural radioactivity in 1896 when he noticed that uranium salts could expose photographic paper without external light. Marie and Pierre Curie later expanded on his work. Becquerel shared the 1903 Nobel Prize with the Curies.

Enrico Fermi led the team that achieved the first controlled nuclear chain reaction at Chicago Pile-1 in 1942, marking the birth of the nuclear age. Alfred Nobel established the Nobel Prize, Lister pioneered antiseptic surgery, and Pavlov worked on classical conditioning.

Louis Pasteur developed the rabies vaccine in 1885, successfully treating Joseph Meister. He also pioneered pasteurization and germ theory. Fleming discovered penicillin, Mendel founded genetics, and Ross discovered malaria transmission.

Marie Curie won Nobel Prizes in Physics (1903, with her husband Pierre and Henri Becquerel) and Chemistry (1911, for discovery of radium and polonium). She remains the only person to win Nobel Prizes in two different scientific fields. Alfred Nobel established the prizes.

Correct answer is (3). 

Humphry Davy discovered nitrous oxide's anesthetic properties (calling it laughing gas) and also isolated several elements using electrolysis. Lavoisier worked on oxygen and combustion, Pascal studied pressure, and Heisenberg developed quantum uncertainty principle.

The Krebs cycle (also called citric acid cycle) was discovered by Hans Krebs in 1937. This fundamental metabolic process occurs in mitochondria and converts nutrients into energy through cellular respiration. The other options are incorrect: Freud was a psychoanalyst, Jenner developed smallpox vaccine, and Fischer was a chemist who studied sugars and proteins.

Joseph Priestley discovered oxygen in 1774 through experiments with mercuric oxide, calling it "dephlogisticated air." While Scheele also discovered it independently around the same time, Priestley published first. However, it was Lavoisier who correctly identified oxygen as an element, understood its role in combustion, and gave it the name "oxygen." Option B is misspelled (Antonie Lavosier should be Antoine Lavoisier).