The powers of the national government are limited
It is important because it lessens, minimize, or reduce competition in the western part of the country, they can determine accurately the time zone of one town from another town – for example, one town might have 6 am whenever the sun rises and another town had 6 am 10 minutes later, they made it possible for towns to lay their own tracks and most importantly; they provide greater efficiency in production, safety, and scheduling.
There are 2 answers that fits the meaning of interest groups. It is letter b and c. Interest groups are also called pressure group. This are group of people or an organization that has the concers and trying to influence public policy in thier favor. They are concerns with various issues or problems that gave them hindrances to win control of the government. They pressure the policy makers by lobbying.