Which simple machine can be described as a rope that is threaded through a wheel or disk?
The correct answer is B - Pulley
A pulley is a simple machine that is used to lift loads. It consists of a wheel on which a rope is placed and the rope is pulled by the person towards himself to lift the load that is tied on the other side of the rope. There are three main types of pulleys: fixed, movable, and compound.
<span>Alveoli are specifically designed to quickly facilitate the exchange of gas from the lungs to the blood. They are very small, but with a very high surface area allowing a greater amount of gases to be exchanged in a comparatively short period of time.</span>
