Mainly they are driven round by a series of cogs and gears, and as you turn a small handle the various parts go round. Some are driven by a cord and pulley system, but these are not as accurate as the geared ones.
Most saturated fats come from animal-based products, like milk, butter, and ice cream; red meat and poultry; and a few oils derived from plants (e.g., coconut oil and palm oil). Unsaturated fats are primarily found in vegetable oils (e.g., olive oil), nuts and nut butters, avocados, and fish.
what is the difference between saturated and unsaterated fatty acids? saturated: solid at room temp, surrounded by hydrogen unsaturated: not surrounded by hydrogen, liquid at room temp