The last group of animals to research may be the most interesting. Most birds share an awesome adaptation: they can fly! This does not make a bird, however. Traits which all birds share are:
Beak with no teeth
The first two allow most birds to fly. Unlike mammals and reptiles, most birds have hollow bones. This makes them very light. Their feathers and lightweight skeletons are physical adaptations. This is a trait which an animal is born with that helps it survive. Soaring through the air is a pretty fun way to travel!