This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: In the last two decades of the 18th century, the theory of polygenism, the belief that different races had evolved separately in each continent and shared no common ancestor, was advocated in England by historian Edward Long and anatomist Charles White, in Germany by ethnographers Christoph Meiners and Georg Forster, and in France by Julien-Joseph Virey. In the US, Samuel George Morton, Josiah Nott and Louis Agassiz promoted this theory in the mid-nineteenth century. Polygenism was popular and most widespread in the 19th century, culminating in the founding of the Anthropological Society of London (1863) during the period of the American Civil War, in opposition to the Ethnological Society, which had abolitionist sympathies. Question: In what century was polygenism most widespread?
19th century

Passage: The Treaty of Paris stood until 1871, when France was defeated by Prussia in the Franco-Prussian War of 1870–1871. While Prussia and several other German states united to form a powerful German Empire, the Emperor of the French, Napoleon III, was deposed to permit the formation of a Third French Republic. During his reign, Napoleon III, eager for the support of the United Kingdom, had opposed Russia over the Eastern Question. Russian interference in the Ottoman Empire, however, did not in any significant manner threaten the interests of France. Thus, France abandoned its opposition to Russia after the establishment of a republic. Encouraged by the decision of the French, and supported by the German minister Otto von Bismarck, Russia renounced the Black Sea clauses of the treaty agreed to in 1856. As the United Kingdom alone could not enforce the clauses, Russia once again established a fleet in the Black Sea. Question: Between what years did the  Franco-Prussian War take place?
1870–1871

Passage: Seattle annually sends a team of spoken word slammers to the National Poetry Slam and considers itself home to such performance poets as Buddy Wakefield, two-time Individual World Poetry Slam Champ; Anis Mojgani, two-time National Poetry Slam Champ; and Danny Sherrard, 2007 National Poetry Slam Champ and 2008 Individual World Poetry Slam Champ. Seattle also hosted the 2001 national Poetry Slam Tournament. The Seattle Poetry Festival is a biennial poetry festival that (launched first as the Poetry Circus in 1997) has featured local, regional, national, and international names in poetry. Question: How often does Seattle send to the National Poetry Slam?

annually