In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.

[Q]: The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger -- Marsden gold foil experiment. After the discovery of the neutron in 1932, models for a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko and Werner Heisenberg. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud. Protons and neutrons are bound together to form a nucleus by the nuclear force.
[A]: who said most of an atoms mass is in the nucleus


[Q]: Las Vegas Stadium is the working name for a domed stadium under construction in Paradise, Nevada for the Las Vegas Raiders of the National Football League (NFL) and the UNLV Rebels football team from the University of Nevada, Las Vegas (UNLV). It is located on about 62 acres west of Mandalay Bay at Russell Road and Hacienda Avenue and between Polaris Avenue and Dean Martin Drive, just west of Interstate 15. Construction of the $1.9 billion stadium began in September 2017 and is expected to be completed in time for the 2020 NFL season.
[A]: where is the las vegas football stadium going to be built


[Q]: In 1969 at a UNESCO Conference in San Francisco, peace activist John McConnell proposed a day to honor the Earth and the concept of peace, to first be celebrated on March 21, 1970, the first day of spring in the northern hemisphere. This day of nature's equipoise was later sanctioned in a proclamation written by McConnell and signed by Secretary General U Thant at the United Nations. A month later a separate Earth Day was founded by United States Senator Gaylord Nelson as an environmental teach-in first held on April 22, 1970. Nelson was later awarded the Presidential Medal of Freedom award in recognition of his work. While this April 22 Earth Day was focused on the United States, an organization launched by Denis Hayes, who was the original national coordinator in 1970, took it international in 1990 and organized events in 141 nations.
[A]:
what was the purpose of the first earth day event on april 22nd 1970