What were the laws passed by southern states to prevent african americans from owning land?

Why did some states believe they had the power to overturn federal laws?

It can be inferred that the dramatic increase in defense spending by germany was the result of. (a) attempts by great britain to take german colonies. ( b) fear of a two-front war against france and russia (c) the need to put down a communist rebellion (d) a competition with the allies to produce atomic weapons

When conducting research for forming a hypothesis, which practice should historians follow?