The movement of a gene from one linkage group to another is called

Find out the correct pair.

Gynaecomastia is the symptom of

Down syndrome is caused by an extra chromosome in the $21$st pair. What percentage of offspring from an affected mother and a normal father will show the effect of this disorder (in $\%$)?

$A$ male individual with $47$ chromosomes due to the addition of an $X$ chromosome suffers from a condition called:

The chromosomal condition $2n-1$ is an example of what?