The last one, 12p 12e 12n
Answer:
I do believe the answer is D. prism
The frequency of the wave is 
Explanation:
The frequency, the wavelength and the speed of a wave are related by the following equation:

where
c is the speed of the wave
f is the frequency
is the wavelength
For the radio wave in this problem,


Therefore, the frequency is:

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Answer:
b
Explanation:
Mass number consist of number of proton and neutron in an atom