Yes, even I think it is better to start from gravity
What is gravity??? It is a resultant force of a natural process.
What is that natural process??? Process of collecting force.
I think story telling way is better to explain about this natural process.
This natural process is like own citizens paying maximum tax to RUN the government.

Planet is like a small government running with help of there own citizens (atoms), this government is located at static center. The citizens inside the government must pay maximum tax to RUN the government.
To run the government, yes this small government (planet) is located inside central government (sun) area of sun, so planet (small government) must pay maximum of its tax to its central or superior government.
Like wise this natural process continues till to its end (from nucleus to planet, planet to sun, sun to galaxy,and galaxy to space).

Is like taking food to live, but giving support for existing.
so gravity is a resultant force not a fundamental force.

"We can't solve problems by using the same kind of thinking we used when we created them.
The difference between genius and stupidity is that genius has its limits. (Thanks to Michael)"

albert Einstein