The statement "An average Star spends 90 percent of its life as a helium-burning main-sequence star" is definitely true.
Stars spend about 90% of their lives in the Main Sequence phase, powered by nuclear fusion of hydrogen in their cores, this is the most densely populated region of the HR diagram.
The overall lifespan of a star is determined by its mass. Since stars spend roughly 90% of their lives burning hydrogen into helium on the main sequence (MS), their 'main sequence lifetime' is also determined by their mass.
Therefore, the statement "An average Star spends 90 percent of its life as a helium-burning main-sequence star" is definitely true.
To learn more about Stars, refer to the link:
https://brainly.com/question/968742
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