You will have to look at whether or not the creator of the source had a really positive or negative outlook on the situation.
If they are -for example- great friends with a bully, they will not tell as much of the truth, but if they are enemies, they may tell a very exaggerated truth to get them in trouble.
You must look for a very neutral feeling on both sides of the matter. If the author has an opinion, more likely than not it will affect the way they share the information
Hitler and his army were the reason for the holocaust.
The answer is A Decreasing tensions with natives, they wanted to give up their land
Answer:
During the cold war, many Americans were accused of espionage.
Explanation: