Why did unions have more power than individual workers to improve conditions

The slave dred scott sued for his freedom because he was born a free man. he had lived in a free state. slavery violated the 13th amendment he had been freed by pres. lincoln.

This law states that the "chinese laborers to this country endanger the good order of certain localities" in the united states. which of these would represent a "locality" that would most likely have wanted this law created and passed? a) dallas b) chicago c) atlanta d) san francisco

Ineed asap! ! what is the name of the system in which each branch of the u.s government can limit the actions of the other branches? a. perpetual union b. division of powers c. cooperative federalism d. checks and balances