What will be the number of linkage groups in maize if it has $10$ pairs of chromosomes?

What is the reason for the absence of hybrids?

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?

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

In female $Drosophila$,linked genes show recombination during meiosis. However,such recombination does not occur during sperm formation in male $Drosophila$. Why?

Sex linkage was first observed by.....