The frequency of the wave has not changed.
In fact, the frequency of a wave is given by:
where v is the wave's speed and 
is the wavelength.
Applying the formula:
- In air, the frequency of the wave is:
- underwater, the frequency of the wave is:
So, the frequency has not changed.
I think it is c I'm only in 7th grade but I'm pretty sure that the answer is c
Answer:
The outbreak of tornadoes that tore across the Gulf and the East Coast Tuesday and Wednesday was unusual for two reasons. For one thing, the severe weather encompassed a significant swath of the country. For another, winter is the least likely time for tornadic thunderstorms.
Explanation:
The outbreak of tornadoes that tore across the Gulf and the East Coast Tuesday and Wednesday was unusual for two reasons. For one thing, the severe weather encompassed a significant swath of the country. For another, winter is the least likely time for tornadic thunderstorms.
And yet tornadoes are an expected part of life in the United States—especially in the multi-state area known as Tornado Alley. (Florida, too, sees a disproportionately high number of tornadoes, because of its frequent thunderstorms.) The United States gets more tornadoes, by far, than any other place on the planet. It averages about 1,250 twisters a year. Canada, which sees about 100 tornadoes per year, is a “distant second,” according to the National Centers for Environmental Information.
