Gene mapping for beak color and feather length in biology what is this

I am not entirely sure about this. So maybe my response can help you find the answer a little better if my answer is not entirely right?

These last three questions are referring to everything you just worked on. So all you would have to do is refer back to your previous answers. Recall that the titles of the "part 1, 2, and 3" are titled "crossing beak color and tail-feather length", "crossing beak color and feather color", and "mapping tail-feather length and feather color".

1.List the distances between each pair of genes:
beak color and tail-feather length: 20 MU
beak color and feather color: 16 MU
tail-feather length and feather color: 4 MU

2.Which two alleles are the farthest apart?
(the one that is 20 MU apart) Y and L

3.Which two alleles are the closest together?
(the ones that are 4 MU apart) L and B