Final answer:
The new technologies in the steel industry in the late 1800s led to increased activity in the construction and automotive industries due to the demand for affordable and high-quality steel.
Step-by-step explanation:
In the late 1800s, advancements in the steel industry, such as the Bessemer process and the open-hearth process, significantly increased the production and decreased the cost of steel. This led to a surge in the construction and automotive industries, both of which required large quantities of steel for the building of infrastructure, buildings, and vehicles.
Consequently, as steel became cheaper and more readily available, it spurred growth and development in these industries, transforming them into key areas of economic activity during the industrial boom.