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.
1 Autism is a spectrum disorder: it may be mild or severe. 2  Many of the symptoms overlap with other conditions such as obsessive-compulsive disorder (OCD) or attention deficit hyperactivity disorder (ADHD).  ASD is a developmental diagnosis. Expression of the syndrome varies with a childâs age and developmental level.