- Nuclear fusion is a kind of process
- Nuclear fusion in a star 's core generates energy for stars to burn / shine
- Therefore, nuclear fusion is the process in a star's core that generates energy for the star

- Nuclear fusion is the process in a star's core that generates energy for the star
- The sun is a kind of star
- Therefore, nuclear fusion is the process in a star's core that generates energy for the sun

Therefore, nuclear fusion is the process in a star's core that generates energy for the sun
Question
What is the process that produces energy in the Sun for billions of years?

Context
- Nuclear fusion is a kind of process 
- Nuclear fusion in a star 's core generates energy for stars to burn / shine 
- The sun is a kind of star