Crossing over is

When a group of genes exhibits linkage,they:

There are three genes $a, b, c$ with percentage of crossing over between $a$ and $b$ is $20\%$,$b$ and $c$ is $28\%$,and $a$ and $c$ is $8\%$. What is the sequence of genes on the chromosome?

What was the phenotypic ratio obtained in the experiment on linkage and recombination performed in Lathyrus odoratus (Sweet Pea)?

Genetic variation is observed in sexually reproducing species.

Two genes $R$ and $Y$ are located very close on the chromosomal linkage map of maize plant. When $RRYY$ and $rryy$ genotypes are hybridized,then $F_{2}$-segregation will show