Describe the difference between gravitational force and strong nuclear force

Gravitational force is much weaker, because it is the force of gravity, or the force that makes smaller objects be pulled towards a much bigger one with a certain amount of force.

Now strong nuclear force, which is very strong, keeps the atomic particles in an atom from separating, and the reason it is so powerful is because the particles in an atom repel each other and this force keeps them from doing .that

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.