Answer:
Criterion and comparison.
Step-by-step explanation:
Autism spectrum disorder may be defined as the developmental disorder that affects the behavior and communication of an individual. This disease can be diagnosed in the early stage of life.
Criterion group and comparison group both are involved in the discovery. Criterion group are used as a standard group in the research. The comparison group is used to compare the two different effects of the research. Here, the children that receive thimerosal vaccine and diagnose with ASD are called criterion group beacuse this group helps to decide the effect of the drug. The group of children that receive thimerosal vaccine but do not diagnose with ASD are considered as comaprison group as they allow to compare the effects of drug.
Thus, the answer is criterion and comparison.