None. They all have exoskeletons that protect the fly's internal workings.
it helps them fly because their bones are lighter and its easier to fly with light bones. But birds with dense bones, such as penguins makes it impossible for them to fly
do fly's have backbons
Birds have hollow bones to help them fly.
Because they fly, there bones need to be hollow to cut down on there weight.
Birds have hollow bones that make them lighter so they can fly more easily.
Birds have hollow bones to help them fly. Solid bones would add to much weight and make it impossible to fly. They have crisscross structures to add support inside the bones.
they are light enough to fly
Birds have hollow bones to help them fly. Solid bones would add to much weight and make it impossible to fly.
birds have hollow bones to help them fly
People can't (or don't) fly since their bones are full of marrow, and to fly, their bones have to be empty, like a birds. Also, people would need wings. That is why i am getting surgery to get my bones cleaned out and working eagle wings patched on tome.
So that the bird is not too heavy to fly and to aid in the intake of oxygen as the bird breaths in flight.
Birds can fly because they have wings, and also because they have hollow bones. Humans can't fly because we don't have hollow bones or wings! Because a Birds bones are hollow my science teacher also calls there bones spongy because they look like that from the inside. And since there bones are hollow it makes them less heavy i would guess and thats why they can fly!!!