twins are such an interesting subject!what can you tell me about them
Well, they are two offspring produced by the same pregancy - kinda like a 2 for 1 sale!
yeah! what type of twins are there?
Well, you can have identical which means the egg splits, or you can have fraternal where there are two separate eggs.  
ohh interesting. what else can you tell me about twins?
There are actually people in the world that are non-related look alikes - they are called doppelgangers.  There  have been several movies and tv shows that involve a set of dopplegangers like Vampire Diaries.