In Drosophila, the allele for a normal grey body colour $G$ is dominant to ebony body $g.$ The following table summarises the results of several crosses

S.No	Cross	Result
$I.$	Strain $1 \times$ gg	All wild type
$II.$	Strain $2 \times$ gg	$1$ wild type $:\;1$ ebony
$III.$	Strain $3 \times$ gg	All ebony
$IV.$	Strain $4 \times$ Gg	$3$ wild type $:\,1$ ebony

Which strains both have the genotype Gg?

A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children ($2$ daughters and $5$ sons). Three of the sons suffer from the given disease but none of the daughters are affected which of the following mode of inheritance do you suggest for this disease

Experimental verification of the chromosomal theory of inheritance was given by

Incomplete linkage is ...$A$.... Complete linkage is ...$B$.... Choose correct option for $A$ and $B$

A distinct mechanism that usually involves a short segment of $DNA$ with remarkable capacity to move from one location in a chromosome to another is called