If interference is complete or $100\%$ then the frequency of observed double crossover will be:

Crossing over is advantageous because it brings about

Crossing over is

Which of the following is true about linkage?
$I.$ It is a phenomenon in which more recombinants are produced in $F_{2}$-generation.
$II.$ More parental combinations are produced in $F_{2}$-generation.
$III.$ Genotypes which are present in $F_{1}$ hybrid reappear in high frequency in $F_{2}$-generation.
$IV.$ It is a phenomenon in which two chromosomes are linked.

Linkage decreases the frequency of

In a chromosome map of maize,two genes $R$ and $Y$ are located very close to each other. When $RRYY$ and $rryy$ genotypes are crossed,the $F_2$ generation analysis shows: