Here is the book for class tomorrow. what is the subject? what is the verb?

Which sentence from a student's reflective essay contains a subject and verb error and needs to be edited? a. in my opinion, some of the voters seemed to need more information about their candidates. b. the documentary showed that dollars are often used instead of rubles in russia. c. the research shows that jackets made of wool are warmer than those made of cotton. d. in my opinion, either the doctors or the chief administrator need to make a quick decision.

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.

What are the benefits of secondary source