The Sun will become a black dwarf when ___. A. the outer regions of the Sun expand B. it has used up all its fuel as a white dwarf C. the Sun moves nearer to the Earth D. the core of th
The Sun will become a black dwarf when ___.
A. the outer regions of the Sun expand
B. it has used up all its fuel as a white dwarf
C. the Sun moves nearer to the Earth
D. the core of the Sun becomes hotter