Final answer:
The remnant of a low-mass star is called a white dwarf, while the remnant of a high-mass star can be a neutron star or a black hole. Low-mass stars become white dwarfs when they exhaust their nuclear fuel and collapse, while high-mass stars undergo supernova explosions and may become either neutron stars or black holes.
Step-by-step explanation:
The remnant of a low-mass star is called a white dwarf. When a low-mass star is ready to die, it undergoes a series of nuclear fusion reactions until it exhausts its nuclear fuel. At this point, the star sheds its outer layers and the remaining core collapses under the force of gravity. The core then becomes a dense, hot white dwarf.
On the other hand, the remnant of a high-mass star is called a neutron star or a black hole. High-mass stars have enough mass to undergo a supernova explosion. Depending on the mass of the collapsing core, it can either become a neutron star if it has a mass below about 3 solar masses, or a black hole if it has a mass above that limit.