1. Infant (from the time of birth to just before he learns to walk)
2. Toddler (12-36 months old, a young child who is just learning to walk)
3. Child (4 – 9 years old)
4. Pre-Teen (10 years old until just before the teenager stage)
5. Teenager (puberty stage before adulthood)
6. Adult (an independent human being)