The right answer for the question that is being asked and shown above is that: "1-4-3-2." (main sequence-->red giant-->supergiant-->white dwarf). Assume that all four H-R diagrams below represent a star in different stages of its life, after it starts to fuse hydrogen in its core.
-The diagram at the left represents the Sun (or any other one-solar-mass star) as a hydrogen-burning main-sequence star, with spectral type G and one solar luminosity. The next diagram shows 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.
-The third diagram 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. The final diagram (far right) 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.
Heavier objects (objects with more mass) are more difficult to move and stop. Heavier objects (greater mass) resist change more than lighter objects. Example: Pushing a bicycle or a Cadillac, or stopping them once moving. The more massive the object (more inertia) the harder it is to start or stop.
