  We say that a star body $K$ is completely symmetric if it has centroid at the
origin and its symmetry group $G$ forces any ellipsoid whose symmetry group
contains $G$, to be a ball. In this short note, we prove that if all central
sections of a star body $L$ are completely symmetric, then $L$ has to be a
ball. A special case of our result states that if all sections of $L$ are
origin symmetric and 1-symmetric, then $L$ has to be a Euclidean ball. This
answers a question from \cite{R2}. Our result is a consequence of a general
theorem that we establish, stating that if the restrictions in almost all
equators of a real function $f$ defined on the sphere, are isotropic functions,
then $f$ is constant a.e. In the last section of this note, applications,
improvements and related open problems are discussed and two additional open
questions from \cite{R} and \cite{R2} are answered.}
