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.
“whose father worked for the railroad” is a subordinate clause as it is a relative clause beginning with the pronoun “whose”. It is particularly used in written English and it refers to possession of things or to make association or connections with other things or people.
In an essay written in a formal style, the kind of tone that the writing should have is: Objective.
An objective tone is a tone where the writer states the facts of a matter. He takes no sides but simply states matters as they are. When writing a formal essay, it important to be objective.
This will require that the facts of the matter are presented and backed by evidence. So, option C is right.
Learn more about formal essays here:
brainly.com/question/3269510
Sentence B. My mother "emigrated" from China and came to the United States uses the underlined word correctly. <u>Emigrate</u> means to leave one country to settle in another, and it implies a permanent move. On the other hand, <u>immigrate</u> is to enter and settle in a foreign country. The difference between these two words is that emigrate is the act of leaving a country and immigrate the act of entering a country.