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.
I believe preschool is for younger children between the ages of 2 and 3. Pre-K would encompass those from 4 up to 5 yrs of age. Generally, parents won't register children in school when they are 5, these children will just enter regular kindergarten. It is really up to the parent and the school/academy they choose.