How does the h-r diagram group stars how a star would move through the diagram during its life

The Hertzsprung-Russell Diagram is a graphical tool that astronomers use to classifystars according to their luminosity, spectral type, color, temperature and evolutionary stage. Stars in the stable phase of hydrogen burning lie along the Main Sequence according to their mass.

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."

vapour or gas assuming atmospheriv pressure