Who used the frequency of recombination ?

The recombination frequency between the genes $a\, \& \, c$ is $5 \,\% \,, b\, \& \,c$ is $15 \,\%,\, b\, \& \,d$ is $9 \%, \,a\, \& \,b$ is $20 \%$ , $c\, \& \,d$ is $24 \%$ and $a \, \& \,d$ is $29 \%$. What will be the sequence of these genes on a linear chromosome? 

Genetic map is one that

The percentage of crossing over will be more if

In Drosophila, long wing and broad abdomen characters are dominant over to characters vestigeal wing and narrow abdomen. A pure breeding Drosophila having long wings and broad abdomen is crossed with a pure breeding vestigeal-winged and narrow-abdomened Drosophila. Two of the $F_1$ individuals were crossed and the following results were produced in the $F_2$ generation Long wing, broad abdomen in $482$ Drosophila. Vestigeal wing, narrow abdomen in $154$ Drosophila. Which one of the following is illustrated by these results