Place the stages of a high-mass star's life cycle in the correct order, from a star's birth to its death.
supernova
protostar
nebula
neutron star
supergiant

Nebula --> Protostar --> Supergiant  --> Supernova --> neutron star

Explanation:

A high mass star starts as a big cloud of dust and gases. This cloud is called a nebula. When these clouds pick up some momentum, it condenses into a protostar.

The protostar will continue to condense because of its increasing gravity. The hydrogen atoms will start to collide and the pressure and temperature will trigger nuclear fusion. This is when the start will enter its main sequence where the outward force of nuclear fusion is balanced with its inward force. It will remain at this state until it runs out of hydrogen atoms.

When hydrogen stats to run out, the gravitational force will be greater than the force of nuclear fusion causing the core to shrink. Nuclear fusion then will start to occur outside the core and the star then expands into a Super giant.

The expansion of the star enables the star to create heavier elements like helium which then undergoes fusion itself and becomes a source of fuel for the star. When helium slowly depletes, it pulled into the core by gravity and all that is surrounding the core will explode , making it a super nova which marks the end of a star.

Two things can result from a supernova, a neutron star or a black hole. For bigger stars, the result would be a black hole. If the mass of the star was at least three times greater than our sun, then it will implode and become a black hole. If it is less, then the core would form a neutron star.

a) carbon, hydrogen

b) carbon, hydrogen, oxygen, nitrogen

c) carbon, hydrogen, oxygen, nitrogen, phosphorus

d) sugar

e) amino acid

f) nucleotide