Inventors and Scientific Discoveries

Nucleotides of DNA were first discovered by Oswarld Avery.

Willard Libby developed radiocarbon dating as a method to measure radioactivity.

This is the correct answer. Hans Christian Oersted was the first person who noticed the deflection of compass needle every time the current was passed through the wire.

Von Humboldt introduced species area relationship curve.

He discovered sex linked inhertance in Drosophila melanogaster.

Coale and Hoover proposed the demographic transition theory in their seminal work 'Population Growth and Economic Development in Low-Income Countries' (1958). They systematically analyzed the relationship between demographic changes and economic development. Dalton and Robbins were economists but not associated with this theory. The theory remains foundational in population economics.

Alexander Wiener was an outstanding leader in the fields of forensic medicine, serology, and immunogenetics. His pioneer work led to discovery of the Rh factor in 1937. Since the progeny could inherit A or O alleles from one parent and B or O alleles from the other, you could be any of the 4 ABO types. Look at the other answers to see how this could be true.

He was an English geneticist. He is famed for first using the term genetics & explaining the study of heredity and biological inheritance.

This option is correct, DNA as an acidic substance present in nucleus was first identifeid by Friedrich Meischer in 1869.

 Antigen antibody reactions were studied by Landsteiner

Karl Landsteiner discovered the ABO blood group system in 1901, for which he received the Nobel Prize. Harvey discovered blood circulation, Ringer developed Ringer's solution, and Pasteur contributed to germ theory. Landsteiner's work on blood antigen-antibody reactions revolutionized transfusion medicine.

Max Planck introduced the concept of quantized energy in 1900, proposing that energy is emitted in discrete packets called quanta. While Einstein, Bohr, and others later developed quantum theory further, Planck is credited as the originator for his work on blackbody radiation.

Lavoisier demonstrated in 1775-1777 that air is a mixture of gases, primarily nitrogen and oxygen. His experiments showed that combustion removed oxygen from air, leaving behind what he called 'azote' (nitrogen). While Priestley and Scheele had discovered oxygen earlier, Lavoisier correctly identified air as a mixture and named the components.

Joseph Priestley discovered oxygen in 1774 by heating mercuric oxide and collecting the gas produced, which he called 'dephlogisticated air'. He observed that candles burned brighter in this gas. While Scheele independently discovered oxygen around 1772, Priestley published first and is credited with the discovery.

Gunpowder was invented in China around 9th century AD. Roger Bacon (13th century) is often credited with introducing knowledge of gunpowder to Europe and documenting its composition, though the actual invention predates him by centuries. In Western trivia, Bacon is commonly attributed as the 'inventor'.