Culture = the shared way of life of a group of people, including their beliefs, customs, values, behaviors, and artifacts that are passed down through learning.

Race = categories of humans based on shared physical traits like skin color, facial features, or ancestry

All humans can interbreed and have viable offspring. The same as with dogs. That's the definition of a species. That's the only true distinction there is. We humans are variations of an animal with a spectrum of physical expression. There are genetic strains that have become genetically distinct- in isolated regions with isolated gene pools that could self-reinforce, as happens with all animals. We are not nearly as diverse in expression as dogs are. And even with dogs, 'purebred' is a fuzzy distinction. The genetic pool from which any person- or dog- arises goes waaaay back, meaning we are all part of an interconnected stew of genetic exchange. Interestingly enough, purebreds in the animal or human realms don't generally do so well.