why are planets round?

Planets are round because the force or gravity on them is soo strong that it pulls them into a rough sphere shape. Example if we were roughly a million times the size we are now the force and gravity on our bodies would be a lot stronger. it is also because most planets are made of gases to the gravity on that planet moves it into a sherical shape eaiser because gases are eiser to tame (In some way)

Gravity is constantly pulling on the mass. Round is a shape that allows the surface to be the same distance from the center no matter where on the surface you are. Things that are too far from that distance get pulled back down over time, and when the surface is less than that distance, pushing happens inside that tend to make the surface rise to that distance.

Lots of things form round shapes for the same sort of reason. water drops, atoms, air bubbles in water.

Planets and Stars are spherical because they are so massive that their gravity pulls them into a roughly spherical shape.

It is nature.If you rotate any other shape it will wobble.It will not be stable.