Most European countries were in expansion of conquest, and Africa was a found ground for it. Many Africans were kidnapped from Western Africa and brought to Portugal. But a reason can be for the economic prosperity the slave trade brought to those countries.
Its letter B
Because Edward III, the king of England. had claimed the throne because his mother was Philip the Fair's daughter.
World War 1 because as Taskmasters said on this website, "Dadaism was an art movement of the European avant-garde, in the early 20th century, which was heavily influenced by World War I. It was anti-war and anti-bourgeois, and had political affinities with radical left. Some of the key figures of the Dada movement were: Hugo Ball, Emmy Hennings, Hans Arp, George Grosz, Max Ernst, Beatrice Wood, Tristan Tzara, Francis Picabia, etc. The movement influenced later styles in art such as Surrealism, Nouveau Realisme, pop art and Fluxus." (I quoted another guy's answer a.k.a. Taskmasters.
