Match the word on the left with the definition on the right.
____ black dwarf e. star left at the core of a planetary nebula
____ white dwarf g. a red super giant star explodes
____ nebula c. what a medium-mass star becomes at the end of its life
____ protostar b. a large cloud of gas or dust in space
____ supernova a. exerts such a strong gravitational pull that no light escapes
____ neutron star d. the earliest stage of a star ’s life
____ black hole f. the remains of a high mass star