All of the ducks shown above are Mallard ducks that belong to the same species (Anas platyrhynchos). Based on these images, which of the following are species characteristics of the Mallard duck?
A.
Mallard ducks have a green head and a yellow bill.
B.
Mallard ducks have a broad bill and feathers.
C.
Mallard ducks have a wingspan of exactly three feet.
D.
Mallard ducks are unable to stay afloat in water.