These four events repeat every 'tropical' year (365 days, 5 hours, 49 minutes), so they become later by about six hours, or (if there has been an intervening leap day) earlier by about 18 hours, from one year to the next.
The three distinctive signs and symptoms of autism include problems with verbal and nonverbal communication, difficulties with social interaction, and repetitive behaviors or narrow, obsessive interests. There are three distinctive symptoms of autism.
Autism Symptoms. Early symptoms of autism Symptoms of autism usually manifest before the age of 3, but may be difficult to identify. The severity of symptom(s), for example, may not be noticed until a few years into childhood.