Answer: Strong Nuclear Force is responsible for making fusion possible in the sun .
Step-by-step explanation:
Fusion reaction is basically the result of the interplay of two opposing forces
1. Attractive Strong Nuclear Force
2. Repulsive coulomb force
Strong nuclear force is a short range force while its magnitude is much greater than the coulomb force . When two nuclei approach each other coulomb force of repulsion between the nuclei (proton-proton repulsion) acts between the nuclei but due high speed as the nuclei come closer strong nuclear force of attraction come into play which has magnitude much more larger than the coulomb force .
The strong force grows rapidly once the nuclei are close enough, and the fusing nucleons can essentially "fall" into each other and the result is fusion and net energy produced. Thus it is the presence of Strong Nuclear Force which makes the fusion possible .