Answer:
Answer to the question as below
Explanation:
In all four H-R diagrams, first we look at the diagram which is at the left and it represents the Sun; it may be any other one solar mass star as a hydrogen burning main sequence star, with spectral type G and one solar luminosity.
In the next diagram it shows that the Sun after it has exhausted its core hydrogen and left the main sequence, making it a sub-giant with energy generated by hydrogen burning in a shell around an inert helium core.
Look into the third diagram which shows the Sun a little later; its energy source is still hydrogen shell burning, but at this point it has expanded in size so much that it is a red giant.
In the final diagram which is located at far right; it shows the white dwarf corpse of a one-solar-mass star; it is hot because it is the exposed core of the dead star, but dim because it is small in size.
