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.
Preschoolers: Ages 2-5. Between ages two and three, many preschoolers begin to use more complicated sentences. However, this does not mean that they understand all of an adult's words or abstract concepts. In fact, preschoolers are often very literal thinkers and interpret ideas concretely. Many are only beginning to think logically and understand sequences of events.