If you want your dog to behave then it must be trained.To train your dog you must take them for walks and teach it to not bark at visitors or bite them. If you can’t train your own dog then you can take them to a training school. Dogs must be fed everyday with good healthy food to make them strong and fit and given clean water to drink. Dogs bark when they are thirsty or angry. A dog can guard your house when you are away at work. Some dogs also work as guide dogs for blind people. All dogs have different appearance.Some are black and some are spotty.Some dogs are furry and very hairy. They also come in different sizes. I like small dogs because I find big dogs scary. There are many different breeds of dogs in the world.