Topic about the shark

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My topic is about sharks.
The sharks are fish that live in the Earth before the dinosaurs.
In my topic I speak of:

1. - the sharks’ habitat
2. - the sharks’ anatomy
3. -the sharks’ reproduction
4. - the sharks’ senses

1- The sharks can live in different habitats, in the oceans, rivers, Lakes, especially in hot waters, but also in cold waters.Some live near the surface and others in deep waters. Others, like the blue shark, live in temperate waters. Some sharks can live in the same region during all their life andothers travel through the ocean.
2- The sharks are a type of fish that does not have bones but only it has cartilages. Some parts of their skeleton, like a vertebrate, are calcified.The cartilage is a fibrous substance and softer than a bone. Our nose and our ears are formed of cartilage. The sharks can have about 3,000 teeth at the same time. The teeth areordered in 5 rows. When a tooth falls or is lost, another of the row of back replaces it. The teeth of the first row are largest and do most of the work. Many sharks do not chew theirfood they gulp it in great pieces.
3- The reproduction of the sharks can be viviparous or oviparous. In the viviparous reproduction the eggs break inside the female´s body and themother feed the babies across the placenta. In the oviparous reproduction the mother deposits the eggs in the ocean and they are not incubated by any progenitor.
4- The sharks havethe same senses that we have (taste, touch, hearing, smell and eyesight) and they also have the sense of the electricity and vibrations in the water.The sharks detect electricitythat is emitted in small quantities by all living animal and this helps them to find their food.The sense of the smell is very sensitive and can detect a drop of blood in kilometres.
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