1 Its cost, on average, is $650, compared to $400 for take-home trays and under $100 for over-the-counter bleaching trays or whitening strips. 2  Results can be unpredictable, depending on factors such as age, heredity and the type of staining that is present.
Plankton (singular plankter) are a diverse group of organisms that live in the water column of large bodies of water and that cannot swim against a current. They provide a crucial source of food to many large aquatic organisms, such as fish and whales.
Plankton (see under marine systems)  1  Neuston (epineuston and hyponeuston)associated with surface tension of water.  2  Nekton free swimming.  3  Benthic (epifauna and infauna) on or in the bottom ooze.   Aufwuchs communities -- organisms attached to rocks or aquatic plants.