Why are virus capsids symmetrical?
The capsid of a virus refers to the protein coat which contains the genomic (genetic ) content of that particular virus.
The capsid is comprised of subunits which are arranged in symmetry to ensure stability of the structure.
The second reason for symmetry is to ensure each protein subunit is exposed to an identical environment as its counterparts.
The most common symmetry noticed in viruses is the icosahedral symmetry, this symmetry is an energy conserving symmetry as particles interact isotropically at the surfaces.