Which of the following is the most likely end for a star that formed from a very small nebular cloud? . black hole . planetary nebula . red supergiant . supernova .

The answer for this question would be Planetary Nebula.

Black holes are created when the star core has a mass of more than 2.5 times of the Sun. In Supernova, for stars with mass of more than 8 times the mass of the Sun, death is signalled by a gigantic explosion: during the first second it can be as bright as a whole galaxy with hundreds of billions of stars. In Red Giants, it is due to explosion of average stars like the Sun. Lastly, in Planetary Nebula, for small stars (that is less than 8 times the mass of the Sun), at the end of the Red Giant phase, the star can’t contract enough to generate the temperatures needed for further nuclear fusion.

Alinear relationship would look like a straight line on the graph. it could have a positive negative or 0 slope. so it could be a line potentially going in any direction but it must be perfectly straight.