Since you haven't provided multiple choices, I'll assume you are looking for an explanation. There were multiple, the most notable being the improvement of the steam engine, the cotton gin, and the cost effectiveness of steel production. The steam engine, developed by James Watt, allowed for increased efficiency and was a huge reason why transportation was now much more of an accessible idea. The cotton gin, made by Eli Whitney, allowed for better productivity when it came to separation of cotton from their seeds and gave way to the thought that slavery was not needed, on a logical and moral mindset.