As far I know, there is no preevolved form of Growlithe. I think you must be mistaking it with Arcanine because Growlithe is the Arcanine's preevoled form and Growlithe only evolves if it is exposed to the Fire Stone.
Steelix.
Onix's final evolution is Steelix, the Steel/Ground-type Pokemon. It can evolve only by trading Onix to another player, while holding a Metal Coat, or Steelix can be found in certain areas in the right game version.
onix evole from gedude
Onix is in Pewter City where Brock is.
Jynx's preevolved form is Smoochum.
As far I know, there is no preevolved form of Growlithe. I think you must be mistaking it with Arcanine because Growlithe is the Arcanine's preevoled form and Growlithe only evolves if it is exposed to the Fire Stone.
Growlithe does not have a pre-evolved form but to evolve it into an Arcanine, use a fire stone.
Steelix.
I believe its the female Pokemon's preevolved form if your breeding something with ditto it will be the other Pokemon not ditto.
You can catch Steelix (Onix's evolution form) on Iron Island and in Victory Road.
No, Steelix is the evolved and final form of Onix
Onix does not have a pre-evolution. It does, however, have an evolution - Steelix, which you can evolve it into by trading it while holding a Metal Coat.
steelex does not evolve for it is a final evolve form of onix
Onix does not have a pre-evolution form currently as of Pokemon Omega Ruby and Alpha Sapphire and has not been announced for the Pokemon Sun and Moon games.
After a certain amount of steps a Pokemon egg will hatch what will be inside will usually be the preevolved form of a Pokemon. For example if you were breeding raichu and ditto you will receive pichu from the egg.
Onix's final evolution is Steelix, the Steel/Ground-type Pokemon. It can evolve only by trading Onix to another player, while holding a Metal Coat, or Steelix can be found in certain areas in the right game version.