a. <u>a protostar reaches a temperature high enough for nuclear fusion to begin.</u>
Explanation:
A protostar is a very young star that is gathering mass a form the stellar mass, supported by the pressure and ends with an inflating gas and the energy generated produces the stars that come from nuclear fusion occurs at the centre of the rotating disk.
Warm air rises up at the equator and moves toward the poles. Global winds do not move directly from north to south or south to north because the Earth spins.
Per capita GDP is often analyzed alongside GDP. Economists use this metric for insight on both their own country's domestic productivity as well as the productivity of other countries. Per capita GDP considers both a country's GDP and its population.
