Different screen sizes

Hi,
Just wondering how to manage different screen sizes in Unity3D. If i publish on IOS and Android there are quite a few to care about when it comes to assets etc. In XCODE i needed to cater for them all.

For 2D stuff we normally just use a fixed height orthographic camera and make sure the important elements can be seen in the narrowest aspect.

In the Scene i can change the screen aspects and it seems like the sprites adjust to the screen size, is that correct?

If so, do i need to have different resolution on my sprites and background when launching, let’s say, an iPhone and iPad app?

If you’re talking about Unity Sprites then I don’t use them so I don’t know.

…or to be correct prefabs.