Answer:
C) when nuclear fusion begins in the core
Explanation:
- <u>The protostar is a main-sequence star that has a core temperature that exceeds abut 10 million K and is needed for the hydrogen to operate efficiently and the </u><u>length </u><u>of this process depends on nature and the stellar </u><u>mass</u><u>, as the huge massive star have a greater and bigger core and fusion takes fast.
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- A protostar is also called as primitive star and represents the earliest phases of the process of the stellar evolution and takes place after it leaves form the main sequence star.
Climate and soil quality varied throughout the land area surrounding the city
<span>A Chilean reporter shares live footage of an earthquake on the Web</span>
