Which scientists proposed the coupling and repulsion theory?

Drosophila melanogaster has $8$ chromosomes in its somatic cell. How many linkage groups will it have?

Which of the following is suitable for the study of linkage?

For the physical association of genes on a chromosome,Morgan coined the term $...............$ and for the generation of non-parental gene combinations,he described the term $...............$.

Who performed the first experiment on linkage and recombination?

Select the correct statement regarding the dihybrid cross experiment.