Answer: heavier , thermal and neutron
Explanation:- Nuclear fusion is a chemical reaction in which two small nuclei combine together to form a heavier nuclei and a lot of thermal energy is released.
In the sun as the fusion of hydrogen nuclei occurs, a large amount of nuclear energy stored in the form of binding energy is transformed into thermal energy.
Example of fusion reaction occurring in sun: deuterium and tritium fuses to produces helium and a neutron and is represented as :
[tex]_1^2\textrm{H}+_1^3\textrm{H}\rightarrow _2^4\textrm{He}+_0^1\textrm{n}+energy[/tex]