The correct answer is additions - those are the types of changes that occur when text has been omitted from a document and must be inserted later.
Hello. Although you showed the book to which the question refers, you did not say which incident the question refers to, as there are many incidents covered in the book. This makes it impossible for your question to be answered, but I will try to help in the best possible way.
The main factor that points to the transition from old forms of war to new forms of war during the first world war was the use of technologies, mainly those driven by the industrial revolution, which gave the army a warlike power never seen before and allowed each army had access to fighter planes, tanks, submarines, toxic gases and others that did not exist in previous wars and that caused much greater destruction.
Answer: I would contend that the right answer is the B) Players often return to a game after a head injury—they.
Explanation: By using a dash or specifically an "em-dash" ( — ) at the end of the sentence, the writer is clarifying or amplifying the information that he or she has already provided (that players often return to a game after a head injury). Options C and D are grammatically incorrect, so they should be discarded. Furthermore, since the two sentences ("players..." and "they do not want...") are not independent, the use of a semicolon (option A) should also be discarded.
It is about Gordon korman using the item as the next future item in the case of the continuing investigation. The protagonist says the character of the secretary is the only territory of the England in the northwest. Therefore the protagonist is saying that Gordon is using the future time telling as the next best item. Good luck :)