In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

[EX Q]: 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.
[EX A]: bayous

[EX Q]: How many things may mirror things with effects?, Context: The three marks of existence may reflect Upanishadic or other influences. K.R. Norman supposes that the these terms were already in use at the Buddha's time, and were familiair to his hearers.
[EX A]: three

[EX Q]: What was A. A. Michelson's profession?, Context: Notable faculty in physics have included the speed of light calculator A. A. Michelson, elementary charge calculator Robert A. Millikan, discoverer of the Compton Effect Arthur H. Compton, the creator of the first nuclear reactor Enrico Fermi, "the father of the hydrogen bomb" Edward Teller, "one of the most brilliant and productive experimental physicists of the twentieth century" Luis Walter Alvarez, Murray Gell-Mann who introduced the quark, second female Nobel laureate Maria Goeppert-Mayer, the youngest American winner of the Nobel Prize Tsung-Dao Lee, and astrophysicist Subrahmanyan Chandrasekhar.
[EX A]:
faculty

