The 6 Groups of Animals

1. Mammals-  Mammals are in the group of vertebrate animals, and they are warm-blooded, they are the only group of animals which gives birth to the young ones and they have fur or hairs on their body and only animals that have mammary glands for producing milk for their young ones. They have lungs to breathe. There are also many kinds of mammals like Kangaroos that have a pouch on their stomach to carry their babies and bat is the only mammal that can fly and platypus that lay eggs and so on.

2. Birds- They are warm-blooded animals. They are a group of animals that can fly, they have wings for flying in the air. They can fly because they are very light in weight. They have a beak for eating. They have a claw for holding the branches of the tree and for standing. They have a four-chambered heart. They have lungs to breathe. They lay eggs and are in the group of vertebrate animals.

3. Fish- They are in the group of vertebrate animals. They are only animals that breathe in water have gills for breathing. They lay eggs. They have fins, scales, and a streamlined body for swimming. They also have warm blood that helps them to survive in cold waters. 

4. Reptiles- They are in the group of vertebrate and egg-laying animals. They are cold-blooded animals. They breathe through their lungs. They have a very slow movement. They have lungs to breathe through.

  

5. Amphibians- They are in the group of vertebrate and egg-laying animals. They are cold-blooded animals. They need water or a moist environment to survive in. They have the most different respiratory system, they can breathe through their lungs and as well as through their skin. They have special skin glands to produce useful proteins. 

6. Invertebrates- They are generally soft-bodied animals as they don't have a backbone, but some of them have a hard shell or covering on their body. There are many different kinds of invertebrates like parasites, insects, jellyfish and etc.