The purpose of the United States signing treaties with Native Americans was so that Native Americans can have land in North America.
The answer to your question is b
The answer is : Efficient
Improved technology allows workers to be more efficient and productive. Technology cut down their working time , and making them use smaller effort with a larger quantity.
Hope this helps
1. 1929 stock market crash
2. Over production in consumer goods
3.lack of credit
4.over confidence in the 1920
5. Rapid bank closures
6.fall in demand and the purchase of consumer goods
7.countries high levels of debt due to war reparations