To date, there is no grass dragon in DragonVale. You may be thinking of the plant dragon. See the related question.
a hybrid- either a rainbow dragon or a flower dragon... hope this helps:)
You don't breed a Kairos Dragon in DragonVale. You have to get parts to complete it.
you breed a ice dragon with a mine dragon
Breed air and and grass you breed grass and air 8hrs incubation You have to do Grass and Flying and if you don't have flying you have to do water and fire but if you don't have water you have to wait and buy it.
You have to breed a plant and a fire dragon.
As of July 2012, there has not been a star dragon in DragonVale.
You have to breed a metal and a water dragon together.
You have to breed a sun and moon dragon together
You have to breed a plasma dragon with a salamander dragon.
Breed the earth dragon with the fire dragon.
To get a Smoke Dragon, breed a fire and air dragon together.
There is no "marsh" dragon in dragonvale but if you are referring to the moss dragon the best way to get it is earth and plant, although you also have a chance to breed the tree dragon.