Final answer:
A breeder can determine if a black male border collie is purebred by examining its pedigree to ensure that all ancestors have black coats.
Step-by-step explanation:
In border collies, black coat is dominant to red coat. If the breeder has a black male dog that has won numerous awards, they would like to use him for breeding. To determine if the dog is purebred, the breeder needs to look at the dog's pedigree.
A pedigree is a chart that helps show family relationships. In the context of a purebred dog, a pedigree demonstrates that the dog comes from a lineage of dogs with the same traits and characteristics.
To establish whether the black male dog is purebred, the breeder would need to trace his lineage and ensure that all the ancestors of the dog also have black coats.