Answer the following question given this paragraph: 

Figure 32.19 Nuclear fusion in the Sun converts hydrogen nuclei into helium; fusion occurs primarily at the boundary of the helium core, where temperature is highest and sufficient hydrogen remains. Energy released diffuses slowly to the surface, with the exception of neutrinos, which escape immediately. Energy production remains stable because of negative feedback effects.


Q: What process converts the sun's hydrogen nuclei into helium?

 Choices:

- solar fission

- nuclear fission

- combustion

- nuclear fusion

A:
nuclear fusion
