Answer:
machines
Explanation:
The factories developed because of the Industrial Revolution. Basically, the factories were manufacturing capacities in which machines were implemented. As the technology was quickly developing, the machines were becoming more and more important in the factories and their productions. The machines gradually reached a level where their efficiency, cheapness, and quickness, were essential in the production process. The human labor is still the most important and without it the machines can not do anything, but by the use of the machines the production has skyrocketed and still continues to grow, thus making their share of work irreplaceable and extremely important.
