Gynaecomastia is a symptom of:

$A$ pregnant woman who has undergone an amniocentesis test finds an extra $Barr$ body in her embryo. Which syndrome is likely to be associated with the embryo?

Allosomic trisomy condition is seen in

$A$ human female with Turner's syndrome:

The Barr body is observed in

When the chromosome number of a given organism has one additional chromosome in one of the homologous pairs,the condition is known as . . . . . .