Who mapped the position of genes on chromosomes by using the frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes?

In a test cross of a dihybrid plant with incomplete linkage,how many types of plants will be produced?

What is the number of linkage groups in humans with respect to $22$ pairs of autosomes?

Genes $A, B$,and $C$ are linked. Genes $A$ and $B$ are closer than $A$ and $C$. Find out the correct option for the given statements:
$I.$ $A$ might be before $B$ and $C$
$II.$ $B$ might be between $A$ and $C$
$III.$ $C$ might be between $A$ and $B$
$IV.$ More crossovers have occurred between $A$ and $C$ than $A$ and $B$.

Genetic recombination occurs through

Mendel studied seven pairs of traits in pea plants,which allow for $21$ possible combinations. If you are told that one of these combinations does not show independent assortment in a subsequent study,what would be your reaction?