Answer:
The correct answer is that blaming an accidental occurence on an internal personal disposition rather than on situational factors is called a Self-Serving Bias.
Explanation:
This term is used when people try to use excuse to protect their esteem and not take responsabilities of their actions.
Connecting the two American coasts made the economic export of Western resources to Eastern markets easier than ever before. The railroad also facilitated westward expansion, escalating conflicts between Native American tribes and settlers who now had easier access to new territories.
Another word for improve could be reform