Sharks are a type of fish with a full cartilaginous skeleton and a
streamlined body. They respire with the use of five to seven gill
slits. Sharks have a covering of dermal denticles that protect their
skin from damage, parasites and improve fluid dynamics; they also have
replaceable teeth. The classic view of the shark is that of a solitary
hunter, ranging the oceans in search of food; however, this is only
true for a few species, with most living far more sedentary, benthic
lives.
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The likely origin of the work shark is from the German word schurke, which means villain.
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