(this answer is only for question one sorry i hope it helps tho) The invention of the cotton gin affected slavery in the U.S. by reducing the work of removing the seeds and was invented in 1794. The purpose of this machine was to separate the seed from the cotton and work by a wooden drum that is covered in small hooks turned behind a mesh. As the drum turns the hooks pull the cotton through the mesh which is large enough to allow the cotton to move freely through it but small enough so that the seeds couldn't go through. It changed the cotton industry by having higher demands for cotton during the time and became one of the most popular cash crops. It impacted slavery by reducing the need for slaves because they created a machine that did the slave's work for them.
(it got a bit sloppy at the end but u can edit it as you need :))