Answer:
Their = to show ownership
There= Showing where something is. (i.e. "Its right there!"
They're= As in "They are"
Explanation:
Autism is a genetic disorder that Is a very common disorder and is passed down through chromosomes. Hope this Helped!
Emilie Claudette Chauchoin
Are you thinking Optometrist? I don't have the list so I'm not sure which one for sure.