Question

question 27
which process changes a protostar/pre - main - sequence star into a full - fledged star?
o the formation of a proplyd
o the start of proto - stellar jets
o the accretion of lots of hydrogen
o the start of nuclear fusion in its core

Explanation:

A protostar becomes a full - fledged main - sequence star when nuclear fusion starts in its core. This fusion process releases a large amount of energy that balances the gravitational collapse, stabilizing the star. Formation of a proplyd, start of proto - stellar jets, and accretion of hydrogen are important in the star - formation process but do not mark the transition to a main - sequence star.

Answer:

the start of nuclear fusion in its core