Question

why do all the birds fly free​

Answer 1

Answer:

all birds fly free because they have hollow bones in them

Answer 2

Answer:

Air rushes through the feathers, creating more lift. Birds don't always have to flap their wings to fly. Once they're up high in the sky, they can also glide, which is kind of like getting a free ride on the air. They only have to flap their wings once in a while.

Explanation:

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