Which of the following is an exception to Mendel's laws?

The lack of independent assortment of two genes $A$ and $B$ in the fruit fly $Drosophila$ is due to:

Genes which are located on the same chromosome are

Select the correct statement regarding dihybrid crosses and linkage.

In a fruit fly,the $X$-chromosome linkage map has a total length of $66$ units,with the yellow body gene $(y)$ at one end and the bobbed hair gene $(b)$ at the other end. What will be the recombination frequency between these two genes $(y$ and $b)$?

In the progeny of a dihybrid cross,the frequency of parental combinations is higher than that of non-parental combinations. This is due to: