What is the main difference between planets and stars?

answer:

a star is a celestial body that produces its own light due to a reaction at its core. there are millions of stars. on the other hand, a planet is a celestial body that has a fixed course, otherwise known as an orbit. the orbit is the pathway that allows the planet to move around a star

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.

a corroding iron, if that's one of your choices