Board Thread:Dragon City Gameplay Questions & Answers/@comment-13933821-20130830055514

I've read breeding system in this page, but I can't find list which dragon are included in difficulty 1, 2, or 3. I'm confused, how do you know it?

DificultyDragons1 DificultyDragons 2 DificultyDragons 3 Some hybrid dragons are in difficulty 1, 2 and 3, so how we distinguish it?
 * Some Elemental Dragons (Sea Dragon and Nature Dragon)
 * Some Hybrid Dragons
 * Some Rare Hybrid Dragons
 * Some Elemental Dragons (Terra Dragon, Flame Dragon)
 * Some Hybrid Dragons
 * Some Rare Hybrid Dragons
 * Pure Dragon
 * Some Pure Elemental Dragons (Pure Sea Dragon, Pure Nature Dragon, Pure Dark Dragon)
 * Some Elemental Dragons (Electric Dragon, Ice Dragon, Metal Dragon, Dark Dragon)
 * Some Hybrid Dragons
 * Legend Dragons
 * Some Pure Elemental Dragons (Pure Terra Dragon, Pure Flame Dragon, Pure Electric Dragon, Pure Ice Dragon, Pure Metal Dragon)

Some rare hybrid dragons are in difficulty 1 and 3, how we distinguish it? 