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.
At age 3, Caring for Your Child states that a small child is no longer a toddler.. Instead, a child of this age is considered a preschooler, even though children younger than 3 often attend preschool. The American Academy of Pediatrics is not the only organization to define toddlerhood in such a manner.