Human height is one of the traits that belong to traits that cannot easily be placed in discrete phenotypic classes (there is not only tall and short people, there is continuous variation of height between them). Such traits are usually controlled by more than one gene (polygenic traits).
On the other hand, a Mendelian trait is controlled by a single locus.
Anything below 165 degrees I believe. (At least that's what it is for a chicken breast which I would think would be the same thing. Let me know if not.) :)
