briefly explain one specific technological advance that stimulated economic growth in the period 1840 to 1857. please help :)

The correct answer to this open question is the following.

Although there are no options attached, we can say the following.

The technological advance that stimulated economic growth in the period 1840 to 1857 in the United States was the invention of the early sewing machine. This important piece of technology was invented by Elias Howe (1819-1867).

The invention represented an important advancement in the textile industry and catapulted the production of textiles in the modern factories in the North East of the United States, specifically in Massachusetts, where some important textile plants were located.

With this invention and the growth of railroads in America, the industry of the United States strengthen and trade goods across the country.