Sharks are a type of fish.
There are hundreds of kinds of sharks.Most are about two meters long.The dogfish shark,however,is less than twenty centimeters in length.The biggest whale shark can grow to twenty meters in length.Sharks do not have bones.The skeleton of a shark is made of cartilage.Human noses and ears are also made of cartilage.
A shark has an extremely good sense of smell.It can find small amounts of substances in water,such as blood,body liquids and chemicals produced by animals.Sharks also sense electrical and magnetic energy linked to nerves and muscles of living animals.
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