How did Diamond answer Yali's question? (Epilogue)

To find the answer to this question, simply look on the
very first page of the Epilogue.  There, Diamond says that he would tell Yali that the
differences between various kinds of people "have been due not to innate differences"
between the kinds of people.  Instead, they have been due to "differences in their
environments."

That is the one sentence synopsis of the
book.  Diamond has argued throughout the book that Europeans came to dominate the world
because of accidents of geography and environment.  He argues that Europeans were lucky,
not innately superior.  They were lucky because they inhabited a part of the world that
was good for agriculture and, therefore, for having a large population that could lead
to having "guns, germs, and steel."