Barr body in mammals represents
All the heterochromatin in female cells
One of the two $X$-chromosomes in somatic cells of females
All the heterochromatin in male and female cells
The $Y$-chromosome in somatic cells of male
The "cri-du-chat" syndrome is caused by change in chromosome structure involving
The resemblance of individuals to their progenitors is called
Which of the following is an inherited trait in man
In which of the following disorder a single protein that is a part of the cascade of proteins involved in blood clotting is affected?
Identical twins are produced when