He suggests the second and third types of feathers were probably used for display. (newscientist.com)
If you plan to add a second or third type of flooring, choose something in a similar color for consistency, and in the same thickness or material for an effortless transition. (marazziusa.com)
The bond that occurs between the second and third type of phosphates is that a great deal of energy is stored, and this can be used to trigger chemical reactions. (personaltraining4u.net)