Discontinuous variation – set number of differences (either yes or no)
Limited number of differences with no intermediates between them, e.g. tongue rolling.
The path discontinued (discontinuous) and the fairy was running out of fairy dust so had to jump the gap to the next path with nothing between them. She would either make the jump (YES) or not make the jump (NO).
Discontinuous variation examples include the following:
The ability to roll your tongue, or not;
Your blood group;
And your gender – whether you are male or female.