Read the excerpt from "code talkers.” although american indian soldiers had effectively used their languages to create and transmit secret messages during world war i, military leaders were reluctant to use the code a second time, fearing that it would no longer be effective. the japanese and german governments had sent students to the united states specifically to learn certain american indian languages. the navajo language, however, was so complex that few people outside the navajo nation itself could speak it. in 1942, it was estimated that only thirty non-navajos spoke the language worldwide. which questions would improve the reader’s ability to understand the military leaders’ fear that the code would no longer be effective? check all that apply. how many people spoke navajo before world war i? was the us government able to figure out other countries’ codes? why did the navajos try to prevent outsiders from learning their language? did any of the japanese or german students learn to speak navajo? what kind of code did the american indians use during world war i?

The correct answers would be questions D " Did any of the Japanese or German students learn to speak Navajo" and E " What kind of code did the American Indians use during World War I".  These are the questions that could help the reader understand the military leader's fear, since if the answers are yes they did learn to speak it, and a simple code, (respectively) then it would be perfectly sane to feel apprehension at using the same code again. Options A, B and C are not relevant because they do not contribute to the subject, for example, it doesn't matter how many people spoke Navajo before World War I, what is important is how many can learn it.

The questions which would improve the reader’s ability to understand the military leaders’ fear that the code would no longer be effective are:

This refers to the use of encryption to pass across information or communication in order to prevent eavesdropping by the enemy so they would not be able to listen.

With this in mind and from the given text, we can see that the military leader was afraid that there use of code was no longer effective because he thought that the enemies could speak Navajo.

Read more about use of codes here:
link

the correct answer would be d, i never like waking up.

explanation:

iambic tetrameter is a meter which is basically a line consisting of four feet of iambic and it is used in poetry. it consists of unstressed syllables followed by a stressed syllable. in this question, the only statement which is giving the feel of being stressed is option d, which says that i never like waking up. it means the person is feeling stressed whenever he wakes up. he never likes to wake up and and whenever he wakes up, he doesn't like it. so a sense or feel of being stressed is in this statement.  

explanation:

it refers to the definition of full-contact sports, where the condition is that the sport must have athletes must "purposely collide with each other