Does the US have a mission to increase democracy and freedom

No

Explanation:

There is nothing in the Declaration of Independence, the founding document of the nation, about any mission to do anything. Nor is there in the Constitution. So any such mission exists only in the heads of people who feel the U.S. ought to be doing this.

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.

d

explanation: