The first simple, one-celled organisms that developed during the precambrian era are called

The Eubacteria was the first form of life; it was a prokaryotic, or single-celled, primitive bacteria. Bacterial microfossils are the earliest known fossils. There were also stromatolites, or microbial growth structures possibly created by eukaryotes, which may have begun to develop during this era.

the answer to number 5 is fort sumter

some american cities felt workers were being oppressed by business monopolies