The best research source for information about the trail of tears would be a Native American textbook. The reason for this lays in the fact that this important historical event was a forced relocation of the Native Americans throughout the country, as it is a situation being imposed on them, they are the main affected group and the victims of foreign interests. The perspective of other parts of this process (The British and early-americans) is biased by those interests, so if you learn from those other sources they would be biased and not precise on what really happened and why it happened.
A western civilization textbook if west of the Mississippi River is western civilization or A Native American Textbook because its from their point of view and is a big part of their civilization and history, not so much Britains or ours. I would say Native Amerixan textbook
The answer that best applies to both the Tang and Song dynasties would be C. A Reliable food production and distribution system. This gave both dynasties the ability to thrive.
The person who perfected the steam engine is the very known inventor and early-day scientist James Watt. His work on the steam engine made it widely used and one of the most profitable and turn-overable areas of the industry during those times.
