How did the group that used ciphers like this one support the war effort? by developing radar technology that made it possible to track planes at night
O by using radios and walkie-talkies" to convey coded messages that could not be deciphered by the enemy
O by forming an elite spy ring that gathered information about strategies and troop movements of enemy armies
O by flying fighter planes into combat zones to provide assistance to ground troops

Which of the following describes a difference between an essay's body paragraph and its conclusion? o a. body paragraphs first introduce evidence, while a conclusion simply reminds readers of evidence. b. body paragraphs act as hooks for the reader, while the conclusion simply restates the essay's claim. c. body paragraphs can be any length, while the conclusion has a set number of sentences. d. body paragraphs restate the essay's claim, while the conclusion proposes claims for future essays.

Which of the following best explains why the rhine-ruhr area became a major industrial area ?

What is an example of a primary source? o a. a dictionary entry o b. a history book o c. an encyclopedia article o d. a recording of a speech