Which of the following represents a complete sentence?
a. independent clause
b. prepositional phrase
c. subordinate clause
d. stand-alone subject

However, the idea of real-life people living in what would become the united states for thousands of years before columbus ever left spain never dawned on me. what would be the best way to revise this sentence for greater clarity? a) however, the fact that columbus left spain thousands of years after people settled what would become the united states never dawned on me. b) it never dawned on me, however, the idea of real-life people living in what would become the united states for thousands of years before columbus ever left spain. c) however, the fact that people were already living in what would become the united states for thousands of years before columbus ever left spain never dawned on me. d) however, the idea never dawned on me that long before columbus ever left spain, real-life people lived for thousands of years in what would become the united states.

How to combine the two sentences in bold.

It is true that prior to 1914 the united states often had been disturbed by events in other continents. we had even engaged in two wars with european nations and in a number of undeclared wars in the west indies, in the mediterranean and in the pacific for the maintenance of american rights and for the principles of peaceful commerce. but in no case had a serious threat been raised against our national safety or our continued independence. what is the theme of this excerpt? a. the responsibility for americans to avoid involvement in war.b. america’s history of international involvement.c. a new kind of threat to american security.d. america’s history as a peaceful nation.