The blades of a helicopter are shaped like what and act as what?

The correct answer highlights that the blades of a helicopter are shaped like airfoils and act as wings. This design is crucial because airfoils create lift as they move through the air. The angled shape of the blades allows them to deflect airflow in such a way that a pressure difference is generated above and below the blade, which is fundamentally what produces lift.

In this context, referring to helicopter blades as airfoils underscores their aerodynamic function, similar to how wings operate on fixed-wing aircraft. This essential characteristic allows helicopters to hover, rotate, and change altitude, differentiating them from other forms of flight.

While other options include terms that relate to different aerodynamic concepts—such as propellers and turbines—they do not accurately capture the specific aerodynamic function of helicopter blades as airfoils. The distinction is important for understanding helicopter dynamics and their operational capabilities.