The bicameral nature of the u. s. federal legislature is responsible for:

a. congress's reliance on committees to review proposals for new laws.
b. the expectation that members of congress will represent their home districts.
c. the division of congressional power between two chambers.
d. gerrymandering in congressional districts during reapportionment.

C. the division of congressional power between two chambers.

Explanation:

The division of powers in the United States is thought to prevent the nation to become a tiranny, or a dictatorship, if a president tries to impose a law where he could be for example re-elected to perpetuity the one of the chambers could stop him, also if one chamber gets corrupted the other and the president can take care of it. Having a two cameras in the legislature allows us to divide the power.

answer: the time zones used to be whatever the local authority wanted them to be. one town might have 6am whenever the sun came up and another town had 6am 10 minutes later.  

the trains had a hard time when their orders said to be at a certain point at 6am.  

6am, but who's 6am.  

the railroads got together and set the time zones more or less along the longitude lines across the country.

explanation:

letter a is the answer