As part of his research on the Civil War, Charlie is reading a book about ironclads (a type of boat) and how they revolutionized naval warfare.

The correct answer to this open question is the following.

Here there is no question, just a sentence. What is your question?

Trying to help we did some deep research and can comment on the following.

The question that is missing is this: "Which of the following is most likely a lens he is exploring?" And unfortunately, you also forgot to include the options for this question.

As part of his research on the Civil War, Charlie is reading a book about ironclads (a type of boat) and how they revolutionized naval warfare. The lens. Which of the following is most likely a lens he is exploring?

the lens of technology.

This is correct because ironclads were a major advancement in the technology of war. Ironclads were modern ships for the time that used steam to move, They were constructed in 1859 and played an important part during the actions of the American Civil War.

she will pay the extra amount

the correct answer is:   "   3.6 % " .

          →   the unemployment rate is:   " 3.6 % " .

explanation:

to calculate the "unemployment rate" :

the "unemployment rate"   =

  [# of people unemployed] /   [working age population]   * 100 %   ;

                =   [9 million] / [250 million]     *   100 % ;

    →     note:   the units of "million" cancel out;

                    since:   " {million} / {million} = 1 " ;

                =   (9 / 250)   * 100 %   ;

                = 0.036 * 100 % ;

                =   3.6 %

answer:   the unemployment rate is:   " 3.6 % " .