Questions 1-3 are about the following passage.

Many people have dogs for pets, but did you know that the dog was the first animal to be domesticated? That means it was the first animal to be kept and cared for by humans. Dogs have been kept as workers, hunters, and friends for much of human history.

Dogs were originally gray wolves, but domestication gradually changed this. Humans have selectively bred dogs for traits that they believed were good. That's how many varieties of dogs came to exist today.

Dogs come in many shapes and sizes. Dogs also have different kinds of coats. Some of them have long hair, while others have short. This hair can come in many different colors and patterns. Dogs also have different skills. Some varieties are good at hunting wild animals, while others are good at herding cattle or protecting people.

Because dogs are closely related to wolves, it might seem like they would be violent. Although some dogs are violent, 15,000 years of domestication has made most dogs friendly to humans. Today's dogs are much easier to train than wild wolves. They respond well to human training: learning to sit, roll over, and even participate in dog shows. Training dogs is a practice that has been improved for many, many years.