Fissured tongue,short stature,and physical or mental retardation are characteristic features of which disorder?

Down's syndrome is caused by an extra copy of chromosome number $21$. What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder (in $\%$)?

What is the genetic disorder in which an individual has an overall masculine development,gynaecomastia,and is sterile?

Down's syndrome occurs in the $21^{st}$ pair of chromosomes due to the presence of an additional chromosome.

Symptoms representing a particular disease due to chromosomal abnormalities are referred to as:

In humans,sometimes during gametogenesis,sex chromosomes do not separate,resulting in a chromosome number of $45$,$47$,or $48$. In this condition,which of the following genotype and phenotype combinations is correct?