Answer:
Explanation:
The radar invented by Robert Watson-Watt, was invaluable to the men who fought the Battle of Britain. The radar allowed Britain to track incoming German warplanes and gave Fighter Command, led by Sir Hugh Dowding, sufficient time to get airborne and attack them
 
        
             
        
        
        
<em>"an economic and agricultural campaign that was led by people supremely unqualified and resulted in disaster"</em>
The Great Leap Forward had a good vision that wanted to increase the economic conditions of China. However, this failed because of certain mishaps in the members qualifications.
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Answer:
Option: Building a timeline of English, French, and Spanish colonies in North America.   
Explanation:
Before the arrival of European, America was inhabitant by the Native population. After Columbus arrival in 1492, many European powers began to arrive to acquire wealth and land for the crown. Many colonies established for settlers in America. 
The decline of the Native population in the United States from the 15th to 17th centuries varies. The Native population began to decline as there was frequent conflict related to the confiscated of the land by the colonists. Many Natives died after coming into contact with Europeans because of the diseases which they were not immune. Disease like smallpox, cholera, malaria, chickenpox, measles, scarlet fever killed thousands of people. The superior weapons like guns and gunpowder helped win battles against the Native Americans. 
 
        
             
        
        
        
Answer:
Japanese smiths traditionally use tama-hagane, steel produced in a tatara smelter from iron-rich sand. Modern smiths making Japanese katana's in the traditional manner still use this type of steel today, now produced in the last operating tatara smelter, located in Yokota, Shimane Prefecture.
while chinese had crucible steel used in the Chinese swords, called chi-kang (combined steel), was similar to pattern welding, and edges of it were often forge welded to a back of soft iron, or jou thieh.