After its main sequence a medium sized star like our sun becomes a red giant, it grows a lot bigger that it's regular size that it will burn earth into ciders, after that it will eject its own nebula and fade away as a dwarf star.
I looked all over the Internet, and saw that there is another option that you didn't include, and which is actually the correct answer.
Bays best facilitate the building of ports, not these options.
Extremely hot, forms in mantle, known as lava in surface, contains dissolved gasses
Increasing wavelength is an indication of a Doppler shift caused by an object moving away from the viewer. Longer wavelengths (of the visible spectrum) are redder, shorter wavelengths are bluer. Objects moving away from you have a red shift, objects moving toward you have a blue shift.
