What is the food sources of a domestic dog?

A domestic dog eats food.
Dog food and meats. Some eat fruits.
well a domestic dog is a carnivore so it will eat meat obviously and dog food and sometimes even fruit .
A domesticated dog will eat nearly anything: trash, grass, bugs, human food, or just dog food. It's not quite safe for them to eat anything other than their dog-designed food, and you might even need to be careful what kind of dog foods you buy.

Some dog food brands are made for a certain kind of dog, like breed or size. Some dog food ingredients you may not agree with due to your beliefs. A lot of dog foods have horse in them. You may want to research some more.