I think the answer to this would be A
Answer:
C. Cytology is the study of cells, while histology is the study of tissues.
Explanation:
the area of the square is: 100
the area of the circle is: 78.5
i THINK if you subtract it, it will be 21.5
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.