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 occupy the pelagic zone of the water column, which is named after its pelagic inhabitants. Plankton may range in size from less than 2 micrometers to organisms larger than 200 micrometers. The category includes many different species of organisms in ocean and freshwater ecosystems. Plankton are divided into phytoplankton and zooplankton. Phytoplankton are photosynthetic and act as the primary producers in an aquatic environment. Zooplankton are heterotrophic and consume smaller plankton. Phytoplankton