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 Spectrum Australia. Characteristics. Autism is characterised by marked difficulties in behaviour, social interaction, communication and sensory sensitivities. Some of these characteristics are common among people on the spectrum; others are typical of the disability but not necessarily exhibited by all people on the autism spectrum.