Distinguish between: Linkage and Recombination.

In a fruit fly,the $X$-chromosome linkage map has a total length of $66$ units,with the yellow body gene $(y)$ at one end and the bobbed hair gene $(b)$ at the other end. What will be the recombination frequency between these two genes $(y$ and $b)$?

Who used the frequency of recombination as a measure of the distance between genes on a chromosome and mapped their position?

There are three genes $a, b,$ and $c$. The recombination frequency between $a$ and $b$ is $20\%$,between $b$ and $c$ is $28\%$,and between $a$ and $c$ is $8\%$. What is the possible arrangement of these genes on the chromosome?

The percentage of recombination between genes $A$ and $B$ is $9\%$,between $A$ and $C$ is $17\%$,and between $B$ and $C$ is $26\%$. What is the correct arrangement of these genes on the chromosome?

The chromosome maps are not accurate maps because