Can you show the full question?
Answer: maximum amplitude of seismic waves as they reach seismographs. So the category the earthquake is such as a 6.0 or a 7.0.
Explanation:
7 billion at the year of 2013
Answer:
They appear to recede from our viewpoint.
That is, their emitted spectra are shifted toward the red (red-shift).
The wave-lengths that are received on earth are somewhat longer because of the "Doppler" shift of the receding atoms.
They are similar because they are all colors in the spectrum and they are different because you cant seperate primary colors but you can seperate secondary