If $F_2$ of a dihybrid cross contains only parental combinations,then Mendel would have discovered .....

The experiment shown in the given figure has been carried out by Morgan to show the phenomenon of linkage and recombination. If in cross $I$,genes are tightly linked and in cross $II$,genes are loosely linked,then what will be the percentage of recombinants produced in cross $I$ and cross $II$ respectively?

Linkage was first suggested by

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

Sex-linked inheritance was discovered by

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