Umm, how is a dog an omnivore compared to a fox?

Because foxes rely solely on a meat based diet, but dogs (being domesticated for thousands of years by humans) require varying amounts of meat in their diet depending on breed and job. There are some breeds of dog who actually require a diet that's more plant heavy with some meat and protein included because that's just how that breed evolved over time with humans. That's a simple version because I didn't want to long rant at you, but I hope that helped!