I believe the answer is D. Thunderstorm
Unstable air indicates that <span>the lowest layers of an </span>air<span> mass is low in temperature. Thunderstorms is more likely to happen if there is unstable air mass because it provide a situation where there is more energy for the Thunderstorms to feed off of.</span>
There’s a first
“clump”/drum beat every half second. That clump will travel about 170m in half
a second. Someone 170m away would do their “clump” as the second “clump” was
taking place. I think. <span>
</span>
To solve this problem we will apply the concepts related to the Doppler Effect, defined as the change in apparent frequency of a wave produced by the relative movement of the source with respect to its observer. Mathematically it can be written as

Here,
= Frequency of the source
= Speed of the sound
= Speed of source
Now the velocity we have that


Then replacing our values,


Therefore the frequency of the observer is 1047.86Hz
Answer:
this may be wrong but I am not sure