$A$ : Crossing over is exchange of genetic material between non-homologous chromosomes.
$R$ : It produces new linkages.

Morgan hybridised yellow-bodied, white-eyed females to brown-bodied, red-eyed males and intercrossed their $F_{1}$ progeny. He observed that

$(a)$ $F_{2}$ ratio was deviated very significantly from the $9 : 3 : 3 : 1$ ratio

$(b)$ Both genes did not segregate independently of each other

$(c)$ Recombinant types are not obtained in $F_{2}$ generation

$(d)$ Both genes segregate independently of each other

Select the correct set of statements :

The map distance between genes $A$ and $B$ is $3$ units, between $B$ and $C$ $10$ units and between $C$ and $A$ $7$ units. The order of the genes in a linkage map constructed on the above data would perhaps be

The linkage map of $X$-chromosome of fruit fly has $66$ units with yellow body gene $(y)$ at one end and bobbed hair $(b)$ gene at the other end. The recombination frequency between these two genes ($y$ and $b$) should be

Genes $A, B$ and $C$ are linked. Genes $A$ and $B$ are more close than $A$ and $C.$ Find out the correct option for the given statements

$I.$ $A$ might be before $B$ and $C$

$II.$ $B$ might be between $A$ and $C$

$III.$ $C$ might be between $A$ and $B$

$IV.$ More crosses has occurred between $A$ and $C$ than $A$ and $B$