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 sex chromosome complement in a male child with Down syndrome?

Relative morphologies of chromosomes of an individual indicate his/her

What would be the number of chromosomes in the ovum (fertilized by a normal sperm) that resulted in the appearance of Klinefelter's syndrome in the offspring?

$A$ human with $45$ chromosomes having only one $X$ chromosome $(XO)$ suffers from which of the following disorders?

Which of the following statements are correct about Klinefelter's Syndrome?
$A$. This disorder was first described by Langdon Down $(1866)$.
$B$. Such an individual has overall masculine development. However,the feminine development is also expressed.
$C$. The affected individual is short statured.
$D$. Physical,psychomotor and mental development is retarded.
$E$. Such individuals are sterile.
Choose the correct answer from the options given below: