  It is noted that in the context of a supersymmetric preonic approach to
unification, gravity, though weak, can play an essential role in determining
some crucial aspects of low-energy physics. These include: (i) SUSY-breaking,
(ii) electroweak symmetry-breaking, and (iii) generation of masses of quarks
and leptons, all of which would vanish if we turn off gravity. Such a role of
gravity has its roots in the Witten index theorem which would forbid
SUSY-breaking, within the class of theories under consideration, in the absence
of gravity.
