33. Which of the following is NOT mentioned in the passage as something that has indicated to scientists the presence of infrasound activity?
Your Answer is
Correct Answer is D
Explanation
Stem Question: Which one did scientists show the existence of infrasound activity?
Item D: L51—53 Here is a metaphor, scientists did not use loudspeakers to detect the existence of infrasound activity. Just compare the rise and fall of sound waves to a loudspeaker.
Item A: L22.
Item B: L66.
Item C: L40.