You are presented with the question "What in the sun causes the sun to produce light?" and the following answer choices: 
- energy of moving objects
 - hydrogen and oxygen
 - heat energy
 - water
 - solar rays
 - rotation
 - nuclear reactions
 - kinetic energy

Now knowing that nuclear reactions in stars causes stars to produce light and and, of course, the Sun is a star, choose the best answer.


 

       nuclear reactions  