Bc they are only out for a limited amount of time
All elements have certain wavelengths of visible light that they can absorb, and later emit. These emission spectra are unique for EVERY element. Since these spectra are unique for each element, identification of the elements can be made from those spectra.
A new alletrope of carbon was found (buckminsterfullerine or
) was discovered using this spectra of red stars.
Both sparked controversy on a political front by bringing new opportunities for political parties to gain more power. Think of the new territory as a way for a weaker side of politics to gain more power in the government.
You should probably use these evidences/terms in your answer:
-North/South/West
-Tariffs
-Expansion, Westward and farmland
-rising tensions/sectionalism
C and B are the most logical. I'd say C, though.