Explain why Bokanovsky's Process is one of the major instruments of social stability.

What the leaders of the brave new world are trying to do
is to make it so that everyone in the society (and especially within each caste) will be
as similar as possible.  They want people to be the same, in part, so there will be
little to no conflict between people and the society will be completely
stable.

That is why the Bokanovsky Process is such an
important instrument of social stability, especially for the lower castes.  By creating
people who are completely identical the leaders of the society can make the people as
identical as possible.  When people are identical, at least according to the book, they
will respond in the same ways and will not come in conflict with one another.  As the
Director says:

Standard men and women; in uniform
batches. The whole of a small factory staffed with the products of a single
bokanovskified egg. "Ninety-six identical twins working ninety-six identical
machines!"