3. Fishes

    Fishes are vertebrates that live in water, their bodies are covered with scales and they breathe by gills. They reproduce by eggs.

   In the picture, we see that fishes have different types of fins: dorsal fin located on the back, caudal fin located on the tail, pectoral fin located on each side, ventral fin and anal fin. Other parts that we see are the eye, nostril, mouth, branchial cleft and the lateral line to receive the vibrations of the water.

   The water enters through the mouth and passes to the gills, where it comes into contact with blood numerous divisions that take the dissolved oxygen in the water and expel carbon dioxide. Then, the water leaves through the branchial cleft.

   There are sea fish such as sardines, cod and hake and other freshwater fishes, such as trout and goatfish .

   For Example: trout , carp , shark , sole , red mullet and rajiformes.

   4. Answer if these sentences are true or false:

    5. Amphibians

    Amphibians have thin and bare skin, without scales.
   When they are young, they live in water and breathe through gills. In adulthood, they are terrestrial or aquatic and usually breathe through lungs but they also breathe through the skin.
   The female lays eggs in the water. Within few days, the tadpoles are born. They have external gills and tail. A few weeks later, the posterior legs appear and then the anterior legs. At the end, gills and tail disappear. Lungs develop and they can live on earth. This process is called metamorphosis.
   For Examples: frog, toad and salamander .

   6. Answer if these sentences are true or false:

   7. Reptiles

   Reptiles are cold-blooded vertebrates, they drag their bodies to walk because they have not legs (snakes) or they are very short (lizards).

   They have pulmonary respiration and the body is covered with scales. They reproduce by eggs. The reptiles are classified into three groups:

   - The lizards are reptiles with four legs and a long tail. They have teeth. For Examples: crocodiles and alligators.

   - The turtles have four legs, beak and a protective shell. They have not teeth. For Examples: turtles and Galapagos tortoises.

   - The snakes are legless reptiles. Some are poisonous like the cobra, the asp of Cleopatra and rattlesnakes. Other snakes are not poisonous, like the boa and python in Indochina.

    8. Indicate if these reptiles are lizards, turtles or snakes:

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