Final answer:
Drag and gravity together are forces that resist airflow over a wing, and this combination is known as drag, not to be confused with lift that is explained by the Bernoulli principle.
Step-by-step explanation:
When drag and gravity act together to resist airflow over a wing, the resultant force is called drag. These forces are essential to understand the flight dynamics of an airplane. The Bernoulli principle helps explain how lift is generated by a wing, which is a different force that acts perpendicular to the wing's surface and supports the plane in the air. The force that directly opposes the forward motion of an aircraft and is combined with gravity is again referred to as drag.