How can a model show the value of pets to humans?

Domestic animals help and are useful to people in many ways, for example, cows provide milk, meat, roosters, eggs, and horses ride, a dog as a friend of a person and a guard of his home, at home, wool, horse and camel milk, that is, kymyz and shubat is used as a medicine, a cat catches mice and gives comfort and warmth to the house, its owner.