Sex chromosomes of a female bird are represented by

In the given figure, the part indicated by $B$ is produced by which process?

Usually,the recessive character is expressed only when present in a double recessive condition. However,a single recessive gene can express itself in human beings when the gene is present on

$A$ family has five daughters and is expecting a sixth child. What is the probability of it being a boy?

There are five daughters and no son in a family. It may be due to

In $Drosophila$,the $XXY$ condition results in a female,whereas in humans,the same condition results in a male with $Klinefelter's$ syndrome. This proves that: