It depends on what pet it is.
*NEW* True, it does depend on what the pet is, but some pets give a card that you can use in battle! Others just look cool and run around your feet.
A pet has talents and skill. Talents are used in the pet derby (I think). The skills your pet can learn can help you in battles.
*NEW* now that there is the starfish pet, and some other pets with talents, when you get it at teen for starfish, you get 11+ max in health. and then at adult in battle it gives a Sprite to you with out even picking it out in your deck! koolio right?! :)
yes you can
yes you can grow a pet in wizard 101
25 spells for death
In NightSide
there is thousands
you can't
no.
you cant
No, they can't.
Some pets naturally have it or you can train it to get talents and it might get a sprite spell
There aren't any stray pets.
A high level such as 42+ is a powerful wizard. They unlock more spells that can do more damage, and spells that can protect them well. If you're talking about the most powerful school, there isn't one.