  We investigate, using high resolution N-body simulations, the density
profiles and the morphologies of galaxy clusters in three models of structure
formation. We show that these properties are closely related to the occurrence
of a significant merging event to a cluster in the recent past. The three
models are: (1) the standard CDM model (SCDM) with $\Omega_0 = 1$,
$\Lambda_0=0$ and $h=0.5$; (2) a low-density flat model (LCDM) with
$\Omega_0=0.3$, $\Lambda_0=0.7$ and $h=0.75$; (3) a CDM dominated open model
(OCDM) with $\Omega_0=0.1$, $\Lambda_0=0$. We find that the clusters in the
OCDM model have the steepest density profiles, their density contours are the
roundest and show the smallest center shifts, among the three models. The
clusters in the SCDM model have contours that are most elongated and show the
largest center shifts, indicating the existence of frequent mergers in the
recent past. The clusters in the LCDM model have density profiles and center
shifts (in their density contours) similar to those in the SCDM model, although
the density contours tend to be rounder. Our results show that, although the
density profiles and morphologies of clusters depend on models of structure
formation, the LCDM model, which is currently considered as a successful
alternative to the SCDM model, can do as well in producing a substantial
fraction of clusters with substructures. This is in contrast to the conception
that this model may have serious problem in this aspect.
