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: When World War II started, tonnage levels at the port decreased and shipping activities were suspended; however, the war did provide economic benefits for the city. Petrochemical refineries and manufacturing plants were constructed along the ship channel because of the demand for petroleum and synthetic rubber products by the defense industry during the war. Ellington Field, initially built during World War I, was revitalized as an advanced training center for bombardiers and navigators. The Brown Shipbuilding Company was founded in 1942 to build ships for the U.S. Navy during World War II. Due to the boom in defense jobs, thousands of new workers migrated to the city, both blacks and whites competing for the higher-paying jobs. President Roosevelt had established a policy of non-discrimination for defense contractors, and blacks gained some opportunities, especially in shipbuilding, although not without resistance from whites and increasing social tensions that erupted into occasional violence. Economic gains of blacks who entered defense industries continued in the postwar years. Question: Why did thousands of new workers flock to Houston?
defense jobs

Passage: The preludes, many of which are very brief (some consisting of simple statements and developments of a single theme or figure), were described by Schumann as "the beginnings of studies". Inspired by J.S. Bach's The Well-Tempered Clavier, Chopin's preludes move up the circle of fifths (rather than Bach's chromatic scale sequence) to create a prelude in each major and minor tonality. The preludes were perhaps not intended to be played as a group, and may even have been used by him and later pianists as generic preludes to others of his pieces, or even to music by other composers, as Kenneth Hamilton suggests: he has noted a recording by Ferruccio Busoni of 1922, in which the Prelude Op. 28 No. 7 is followed by the Étude Op. 10 No. 5. Question: What piece of Bach's did Chopin take inspiration for his preludes?
The Well-Tempered Clavier

Passage: The earliest known chemical evidence of barley beer dates to circa 3500–3100 BC from the site of Godin Tepe in the Zagros Mountains of western Iran. Some of the earliest Sumerian writings contain references to beer; examples include a prayer to the goddess Ninkasi, known as "The Hymn to Ninkasi", which served as both a prayer as well as a method of remembering the recipe for beer in a culture with few literate people, and the ancient advice (Fill your belly. Day and night make merry) to Gilgamesh, recorded in the Epic of Gilgamesh, by the ale-wife Siduri may, at least in part, have referred to the consumption of beer. The Ebla tablets, discovered in 1974 in Ebla, Syria, show that beer was produced in the city in 2500 BC. A fermented beverage using rice and fruit was made in China around 7000 BC. Unlike sake, mould was not used to saccharify the rice (amylolytic fermentation); the rice was probably prepared for fermentation by mastication or malting. Question: When does evidence show the earliest known barley beer was produced?

circa 3500–3100 BC