The frequency of recombination will be higher if.....

Give differences: Crossing over and Linkage.

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$:
Mendel's law of independent assortment does not hold good for the genes that are located closely on the same chromosome.
Reason $(R)$:
Closely located genes assort independently.
In the light of the above statements,choose the correct answer from the options given below:

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

The number of linkage groups in a cell having $10$ pairs of chromosomes is.....

Incomplete linkage is $A$. Complete linkage is $B$. Choose the correct option for $A$ and $B$.