Question

21. What was significant about the inventions of Samuel Slater and Eli Whitney?

Answer 1

@Opcode

Answer 2

Eli Whitney's cotton gin made cotton into a profitable crop for the Northern factories, but also strengthened the need for slavery in the South for labor to run the cotton gins. So Whitney's invention made the decision of what the North and South would manufacture.
Samuel Slater created the first successful textile mill in 1793. "Father of the American Industrial Revolution" (a phrase coined by Andrew Jackson). So pretty much both their invention were important to the Industrial Revolution.