What helps explain why the human gene pool is homogeneous?

Question

what helps explain why the human gene pool is homogeneous?

Answer 1

The human gene pool is not homogeneous.  To be homogeneous, the genomes of the entire species would have to be the same.  This is not the case.  

One example, some people have genetic diseases, e.g., phenylketonuria, that others do not have.  This shows that the genome is not homogeneous.

Some parts of the genome are highly conserved and vary little across the species.  However, other portions of the genome can vary considerably.  This is the reason that we do not all look like identical.