All the deserts are found at 30<span>°N because
</span><span>Hot air from the equator rises, then cools, moisture is lost, and the dry air comes down at 30 degrees north and south</span>
Because it helps the environment strive and keep its self alive my controlling populations and bringing in new ones
Given that,
The speed of a wave, v = 200 m/s
Wavelength, 
We need to find the frequency of this wave. The relation between wavelength, frequency and the speed is given by :

So, the frequency of this wave is 100 Hz.
Answer:
Spikes are provided in the shoes of athletes so as to increase the friction and prevents from falling down.
so option C. is the answer
A plant and animal cell is eukaryotic
a eukaryotic cell has a nucleus instead of floating DNA which a prokaryotic cell has