ИСТИНА

Basing on my recent observational results on the stellar population properties in the disks and bulges of S0 galaxies, I propose a new paradigm for disk galaxy formation and evolution. According to this new scenario, all disk galaxies are born as lenticular galaxies at z>2. Later many of them form thin disks through external cold gas accretion and become spirals. In dense environments, in clusters and rich groups, resources of external cold gas accretion are absent, so in dense environments primordial lenticular galaxies remain S0s up to the present epoch.