International unit corresponding to the biological activity of a defined mass of a reference standard; used chiefly to express the biological potency of certain vitamins.
Feathers characterized by a vascularized calamus and usually incompletely develo...
"In glass"; term for experimental extracorporeal observations (outside the livin...
"In the living"; term for experimental observations in the living organism.
An individual produced by mating related parents.
A group of individuals deliberately bred by inbreeding with a greater or lesser ...
Reduction in vigour, fertility and performance appearing in the offspring of rel...