The process that takes place as a tadpole (蝌蚪) changes into a frog is ____.
A. digestion (消化)
B. metamorphosis (变形)
C. photosynthesis (光合作用)
D. protection
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____ is the only mammal capable of true flight.
A. The bald eagle
B. The flying squirrel
C. The bat
D. The penguin
Chickens eat food using their_____
A. beaks
B. mouth
C.teeth
D. claws
Elephants are often killed because hunters want to sell their_______
A. horns
B. tusks
C. feet
D. tails
Geese, ducks and other birds are covered in_____
A. fur
B. feathers
C. hair
D. spikes