What makes stars produce energy? a)gravity b)hydrogen c)nuclear fusion d)nuclear fission answer and me

C) Nuclear fusion

Nuclear fusion is the process where 4 hydrogen atoms in a star combine together at high temperatures and pressure into 1 heavier helium atom.

nuclear fusion

Explanation:

It makes the stars shine brightly

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

there is none because earth is stationary and flat.