What you need to know about dogs
First, you have to care about your dog.If you care about your dog then you would give them toys,love,shelter,food and water.Baths and runing are needed often.
Second,you have to know about breeds of dogs.A few of dog's are boxers,golden retriver,pit bull,chihuahuas, and bull dogs.knowing your the differnt breeds is important because if you don't you'll never know which breed is the best for your family.
Last,how are they useful?There useful because they can protect your family,there good for hunting , and even helping blind people. Thats why dogs are good for famliy
Finally,dogs are a big hand full because dogs can slober every day and they even get hair every were.Sometimes they stink really bad,so be very careful or your going to get hair and slober,and you'll probably stink bad or your friends is probably are not aloud to be around dogs.So know that you need to know is care about them,know your breeds, and know that thier useful.
Link 1: Dogs on Wikipedia
Link 2: Police dogs on HowStuffWorks