Question

A type of intellectual developmental disorder called ______ is found in individuals with an extra copy of chromosome 21.

a. Down syndrome
b. Fragile X syndrome
c. Chromosome 21 disorder
d. Specific learning disorder

Answer 1

Down syndrome is an intellectual developmental disorder characterized by an extra copy of chromosome 21, known as Trisomy 21, and leads to distinctive physical features and varying degrees of developmental disabilities.

Step-by-step explanation:

The type of intellectual developmental disorder found in individuals with an extra copy of chromosome 21 is a. Down syndrome. Down syndrome, also known as Trisomy 21, is a genetic condition where individuals have 47 chromosomes in their cells instead of the usual 46, because they have three copies of chromosome 21. This results in a range of characteristic physical and mental traits and varying degrees of intellectual and developmental disabilities.

The most common cause of Down syndrome is a chromosomal nondisjunction during the process of meiosis, which leads to an embryo having an extra chromosome. The likelihood of this nondisjunction increases with maternal age, particularly in women over 36. Down syndrome presents with specific physical features, intellectual disability, and an increased risk for certain health issues like congenital heart defects and vision problems. Despite these challenges, many individuals with Down syndrome lead fulfilling lives with proper support and resources.