It is to have understanding or knowledge concering a specific matter.
Answer:
Parallelism
its balancing his speech, making what he says feel impactful
Answer: I believe it would be letter (b)
Explanation: I had to answer this question yesterday and I am pretty sure this is the answer. Because it asks ¨the narrator gives an example of why oxygen is vital to climbers on Mt. Everest. How does the narrator develop this concept in the rest of the narrative?¨ so this is really the only plausible answer regarding the question.