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 are primarily divided into broad functional (or trophic level) groups: 1  Phytoplankton (from Greek phyton, or plant), autotrophic, prokaryotic or eukaryotic algae that live near the water surface where there is sufficient light to support photosynthesis.