Final answer:
Down syndrome is recognized scientifically through chromosomal analysis, specifically by observing three copies of chromosome 21. It is a genetic disorder characterized by physical and intellectual impairments.
Step-by-step explanation:
Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21, also known as trisomy 21. It is recognized scientifically through chromosomal analysis, where the presence of three copies of chromosome 21 can be observed. This can be done through karyotyping, which involves staining chromosomes and examining them under a microscope.
Down syndrome is characterized by physical and intellectual impairments. Some common physical features include a specific facial appearance, low muscle tone, and a shorter stature. The severity and range of symptoms can vary greatly among individuals with Down syndrome.