The US Constitution contains which two of the following concepts?

The correct two items:

limited government

protection for individual liberties

Those two ideas are tied together.  The United States was founded on the idea of protecting individual liberties, which the American colonists felt were being infringed by Great Britain's government.  In the Declaration of Independence, that purpose for forming the new nation was stated -- that to secure the rights of life, liberty, and the pursuit of happiness, a government is established by the consent of the governed.

So, the Constitution of the United States sought to protect individual rights.  The closing words of the Constitution's Preamble assert that the Constitution was being established to "promote the general Welfare and secure the Blessings of Liberty to ourselves and our Posterity."   The Constitution then follows, outlining and limiting what the powers of the government would be, so that the government always was existing for the sake of "the general welfare" and "the blessings of liberty."  The founders did not want the government to become self-serving or achieve a level of power that allowed it to trample on individual liberties.

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: