Which of these best describes heat transfer through conduction?

a) heat transfer as electrons are excited in atoms.
b) heat transfer by the emission of pure energy waves.
c) heat transfer by a liquid or gas flowing over an object.
d) heat transfer by molecules colliding with adjacent molecules.

I'd go for D here. It also fits in with the idea of thermal expansion - as something is heated up, molecules vibrate and maybe collide. they vibrate with bigger amplitudes, so taking up more space, so expanding. maybe

with this one i know the answer in craters one reason i looked it up and i learned about it there is my evidence