Answer:
the sled dogs could travel further without rest
I believe it was because of fear. At the time, many Asian (Chinese especially) people moved to America in search of a better life. Then, the Gold Rush was a thing because there was a lot of it so any worker was welcome. However, as the gold began to be depleted, foreign laborers were wanted less and less. Eventually, the fear of competition grew so strong that President Chester A. Arthur ratified the Chinese Exclusion Act in 1882, thereby denying them access into America.
Italy was already in control of the major routes to the east.
Adding on to the first answer ^^^
Primary sources can also be unreliable as they are biased depending on the source.
If comparing histories of different countries, they tend to describe more victories rather than failures. Also, having a picture as a primary source can be misleading as it can be interpreted in different ways. Sources written in the first person can also have their own biased from the environment the author has lived in.
