Difference Between Convergent and Divergent Evolution. When considering living organisms, evolution can be defined as the development of differentiated organisms from less differentiated pre-existing organisms over the course of time. There are many sources, which provide evidence to the theory of evolution.
You're apparently differentiating between daycare and preschool, right? Private preschools (about $500 per month for three days per week, 9:00a to 1:00p) typically have a minimum age of 30 months (2.5 years) and potty-trained.
Children enter kindergarten during ages five to six, and many states do not begin mandating education until age seven. However, whether it is mandatory or not, it is still highly encouraged. Though kindergarten is more formal, it still qualifies as early childhood education because students are under eight years old.