B. it. ch, now you broke, where the paper you touchin'?

Which training principle states that exercising a certain body part are practicing a particular skill primarily develops that part or skill

Ijust want the meaning to life (no wrong or right answers i just want your true opinion)

Used primarily for thickening sauces and soups, a (paste/roux/stock) is made from a (1: 2/2: 1/1: 1) fat and flour.