Hydrogen is the primary fuel for stars. As the hydrogen atoms fuse together to form atoms of helium, a small amount of mass is converted into a large amount of energy. Examine how each star's "fuel gauge" changes over time.

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The greater a star’s mass, the stronger the inward force of gravity and the higher the pressure and temperature in its core. The rate of fusion increases with temperature, causing hot, massive stars to consume fuel much more rapidly than cooler, less massive stars.

2. Which size star uses up its available hydrogen most quickly? Explain your answer.