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

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.
bayous

The most heat-treatable alloys are decided but only?, Context: Conversely, most heat-treatable alloys are precipitation hardening alloys, which produce the opposite effects that steel does. When heated to form a solution and then cooled quickly, these alloys become much softer than normal, during the diffusionless transformation, and then harden as they age. The solutes in these alloys will precipitate over time, forming intermetallic phases, which are difficult to discern from the base metal. Unlike steel, in which the solid solution separates to form different crystal phases, precipitation hardening alloys separate to form different phases within the same crystal. These intermetallic alloys appear homogeneous in crystal structure, but tend to behave heterogeneous, becoming hard and somewhat brittle.
Conversely

The empire expanded into what modern country?, Context: The Kushan Empire expanded out of what is now Afghanistan into the northwest of the subcontinent under the leadership of their first emperor, Kujula Kadphises, about the middle of the 1st century CE. They came of an Indo-European language speaking Central Asian tribe called the Yuezhi, a branch of which was known as the Kushans. By the time of his grandson, Kanishka, they had conquered most of northern India, at least as far as Saketa and Pataliputra, in the middle Ganges Valley, and probably as far as the Bay of Bengal.
India