Flight Is an Important Means of Locomotion for Many Animals

Flight is an important means of locomotion for many animals. Which of the following statements about flight is INCORRECT?

A) In most birds, it is the downstroke of the wings during powered-flight that creates most of the useful lift.
B) During powered flight, the upstroke of the wings simply returns the wing to a position for the next downstroke.
C) Birds with low wing loading are very agile and able to easily change direction.
D) Hovering is energetically favourable as it allows the animal to remain in the same position.
E) Active flight is extremely energy-demanding, but for a given body mass is more efficient than walking.