What is an example of a complex machine?

A wheelbarrow is an example of a complex machine because it combines two or more simple machines to perform a task more efficiently. Specifically, it incorporates a lever and the wheel and axle systems. The lever in the wheelbarrow allows for increased force, enabling the user to lift and move heavy loads with less effort. The wheel and axle facilitate movement, allowing the wheelbarrow to roll smoothly over surfaces. This interaction among the individual components illustrates how complex machines operate by integrating simpler mechanisms to enhance functionality and effectiveness in carrying out specific tasks.