Animals That Fly
A) Use Muscle-Powered Wings Capable of Sustained $\degree$

Animals that fly

A) use muscle-powered wings capable of sustained flight.
B) are required to produce a lift force as the air passes over the wings to overcome the effect of gravity.
C) produce lift force in the direction of their movement to enable flight.
D) create an aerofoil effect where the air moves faster over the lower surface of the wing to provide upward movement.
E) overcome the drag force of the air by increasing the angle of attack of the wing to more than 20 $\degree$ .