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which is a possible sequence in the life cycle of a massive star
supernova, star, black hole, planetary nebula, super red giant, protostar

super red giant, protostar, nebula, star, neutron star, supernova

planetary nebula, super red giant, protostar, supernova, star, black hole

nebula, protostar, star, super red giant, supernova, neutron star

The correct sequence in the life cycle of a massive star is:

1. Nebula
2. Protostar
3. Star
4. Super red giant
5. Supernova
6. Neutron star

Therefore, the correct option is: nebula, protostar, star, super red giant, supernova, neutron star.

To determine which is a possible sequence in the life cycle of a massive star, let's break down the different stages and see which sequence aligns with our understanding of stellar evolution.

1. Protostar: This is the initial stage where a cloud of gas and dust begins to collapse under the influence of gravity, eventually forming a dense core.

2. Nebula: As the protostar continues to collapse, it forms a nebula - a cloud of gas and dust surrounding the core.

3. Star: The protostar reaches a point where nuclear fusion ignites in its core, generating energy and heat. It becomes a main sequence star, powered by the fusion of hydrogen into helium.

4. Red Giant: When the fuel in the core of a star starts to deplete, it undergoes changes and expands, becoming a super red giant.

5. Supernova: Eventually, a red giant will reach the end of its life. This stage is marked by a massive explosion called a supernova, where the outer layers are ejected into space, while the core collapses.

6. Neutron Star/Black Hole: Following a supernova, the core can either collapse into a dense remnant known as a neutron star or convert into a black hole if the mass is sufficient.

Now let's examine the given sequences:

1. Supernova, star, black hole, planetary nebula, super red giant, protostar: This sequence does not align with the stages of stellar evolution. A supernova occurs after the star phase, so this order is incorrect.

2. Super red giant, protostar, nebula, star, neutron star, supernova: This sequence also does not match the established stages. A super red giant does not occur after a protostar, rather it is a later phase in stellar evolution.

3. Planetary nebula, super red giant, protostar, supernova, star, black hole: This sequence aligns with the described stages of stellar evolution. First, a planetary nebula forms from a dying star, followed by the super red giant phase, then the protostar stage. Afterward, a supernova occurs, leading to the formation of a new star or a black hole.

Therefore, the correct answer is:
Planetary nebula, super red giant, protostar, supernova, star, black hole.