In higher unisexual animals,one pair of chromosomes is not identical in two sexes. It is called as . . . . . . .

$A$: $XO$ type sex determination is found in a large number of insects.
$R$: Some of the sperms bear the $X$-chromosome,whereas some do not.

Given below are two statements.
Statement $I$ - $X$ Chromosome has a large amount of euchromatin and a small amount of heterochromatin.
Statement $II$ - The homologous region of the $X$ Chromosome contains a smaller number of genes than the $Y$ Chromosome.
In the light of the above statements,select the correct option given below:

The presence of hair on the pinna of the ear in males is known as what?

$A$ man affected by a certain disease marries a normal woman. They have $8$ children ($3$ daughters and $5$ sons). All the daughters suffer from their father's disease,but none of the sons are affected. What type of inheritance can you suggest for this disease?

Sex chromosomes of a female bird are represented by