There are many answers to this question
The muscle pulling on a bone often works like a type of simple machine called a lever. Most of the bones of the limbs (arms & legs) act as levers for the body. I hope that this is the answer that you were looking for and it has helped you.
Most likely clay, silt and sand are to be found in samples of rocks.
carbohydrates
they are like fat but they are used in your body and hold water whitch makse people look bloted