Question

what is the proper life cycle of a sun - like star?
red giant
main sequence star
stellar nebula
planetary nebula
white dwarf

Explanation:

A star like the Sun begins as a stellar nebula (a cloud of gas and dust). Gravity causes the nebula to collapse, forming a main - sequence star (where nuclear fusion occurs, fusing hydrogen into helium). As the hydrogen fuel in the core runs out, the star expands into a red giant. Eventually, the outer layers of the red giant are shed, forming a planetary nebula. The remaining core becomes a white dwarf.

Answer:

Stellar Nebula → Main Sequence Star → Red Giant → Planetary Nebula → White Dwarf