In any game of Pokemon, the only way a Growlithe evolves is via the use of a Fire Stone.
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You aren't able to evolve Growlithe by level, but you would have to use a fire stone to evolve it.
eevee,
To evolve Mantyke in pokemon black/white 2 you have to level it up with a remoraid in your party then it will evolve into mantine
In Pokémon White 2, Magneton will evolve into Magnezone once it levels up while in the Chargestone Cave.
Have it hold an Elctirizer and Trade it.