I think it's wavelength
Hope I helped.
Here are the answers to the question. Make sure to give a valid reason, please.
A. the sum of the protons and neutrons in one atom of the element.
B. a ratio based on the mass of a carbon-12 atom.
C. a weighted average of the masses of an element's isotopes.
D. twice the number of protons in one atom of the element.
red hot is hot, but other colours are even hotter. stars may be hotter than red hot.
there is also something calle the red shift.
The correct order they go in is "1-4-2-3" The correct answer is D.
