In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
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Question: The expansion of what further cemented Houston's emergence as a powerhouse commercial city?, Context: By 1860, Houston had emerged as a commercial and railroad hub for the export of cotton. Railroad spurs from the Texas inland converged in Houston, where they met rail lines to the ports of Galveston and Beaumont. During the American Civil War, Houston served as a headquarters for General John Bankhead Magruder, who used the city as an organization point for the Battle of Galveston. After the Civil War, Houston businessmen initiated efforts to widen the city's extensive system of bayous so the city could accept more commerce between downtown and the nearby port of Galveston. By 1890, Houston was the railroad center of Texas.

Answer: bayous

Question: Why did using the method Bach didn't use, gain traction?, Context: The theories surrounding equal temperament began to be put in wider practice, especially as it enabled a wider range of chromatic possibilities in hard-to-tune keyboard instruments. Although Bach did not use equal temperament, as a modern piano is generally tuned, changes in the temperaments from the meantone system, common at the time, to various temperaments that made modulation between all keys musically acceptable, made possible Bach's Well-Tempered Clavier.

Answer: it enabled a wider range of chromatic possibilities in hard-to-tune keyboard instruments

Question: what race is mentioned first?, Context: NASCAR (headquartered in Daytona Beach) begins all three of its major auto racing series in Florida at Daytona International Speedway in February, featuring the Daytona 500, and ends all three Series in November at Homestead-Miami Speedway. Daytona also has the Coke Zero 400 NASCAR race weekend around Independence Day in July. The 24 Hours of Daytona is one of the world's most prestigious endurance auto races. The Grand Prix of St. Petersburg and Grand Prix of Miami have held IndyCar races as well.

Answer:
Daytona 500