What is the clearest signature distinguishing a high-mass giant core from a lower-mass one?

Answer

The existence of layers of heavier element fusion

The existence of successive shells fusing elements heavier than carbon and oxygen (like neon, oxygen, and silicon) is the clearest signature differentiating a high-mass giant core from a lower-mass one.

What is the clearest signature distinguishing a high-mass giant core from a lower-mass one?
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