Slate is much more commonly found in wet areas, especially around rivers in the United States, so it wouldn't be very available to Natives who were more inland.
Jim Crow laws were laws at the state and local level in, primarily, the Southern United States, that enforced segregation of the races.
Universal healthcare should be the answer
So we know when certain things in history took place. Its hard somtimes to remember/memorize all the dates, but timelines do help.
Hope this helps :D
Answer:
If they didn't use air blockade then the people in Berlin could not have escaped from the Soviet blockade.
Explanation: