  Two main types of models have been suggested to explain the long durations
and multiple peaks of Gamma-Ray Bursts (GRBs). In one, there is a very quick
release of energy at a central site resulting in a single relativistic shell
that produces peaks in the time history through its interactions with the
ambient material. In the other, the central site sporadically releases energy
over hundreds of seconds forming a peak with each burst of energy. We present
three kinematic arguments against a single relativistic shell. These arguments
are based only on symmetry. We show that the average envelope of emission of
GRBs is a linear function rather than the power law expected for a single
relativistic shell. We show that presence of gaps in GRBs is the strongest
argument against a single relativistic shell. We estimate that the fraction of
a single shell that can produce gamma-rays in a GRB with multiple peaks is
about 0.001, implying that single relativistic shells require 1000 times more
energy than previously thought. We conclude that either the central site of a
GRB must produce 10^{51} erg/s for hundreds of seconds, or the relativistic
shell must have structure on a scales the order of sqrt(epsilon)/Gamma, where
Gamma is the bulk Lorentz factor and epsilon is the efficiency.
