To my mind, the correct answer is “to help the reader understand how the fuel system on a spacecraft works to help the reader understand the difficult decisions faced by Mission Control”. The aim of including a problem-solution text structure is to organize the author´s ideas in a way that helps the audience to gain understanding of the text. In addition, this device is very useful to call the attention of the audience and to make the text more appealing to them.
The correct sentence is C, because 'driven' is the past participle, part of the present perfect tense. Present participle would be 'driving', it has -ing form, whereas B is not correct because 'helped' is just past, not a past participle.
Answer:
b
Explanation: Torrey clearly said "I think uniforms are a good idea".
Answer: they defined American freedom as the freedom to own guns freedom to self govern and freedom of speech.
Explanation: This was also part of the constitution our founding fathers made it that all men are equal.