Final answer:
Trisomy 21, or Down Syndrome, is the most frequently seen autosomal aneuploidy in humans, characterized by specific physical and developmental features, with higher prevalence related to greater maternal age.
Step-by-step explanation:
The Most Frequently Seen Autosomal Aneuploidy
In humans, the most frequently seen autosomal aneuploidy is Trisomy 21, which corresponds to Down Syndrome. Aneuploidy refers to a deviation from the normal chromosome number in a species, which includes conditions like monosomy (loss of one chromosome) or trisomy (gain of an extraneous chromosome).
Monosomic zygotes usually do not survive, while trisomy of certain smaller chromosomes can lead to survival for varying times. Trisomy 21 is the most common among viable births, characterized by unique physical features, developmental delays, and it is correlated with increased maternal age.