Describe the differences between a fertilized egg and an unfertilized egg.
Answer:
just make up a fake story it would be way easier
Birds live virtually everywhere on Earth because they have evolved endothermy, the ability to use their metabolism to maintain a constant body temperature.
Birds belong to the class aves; they have an extremely efficient, one way breathing system with additional air sacs. Flying birds have strong, hollow bones and powerful flight muscles. Most birds can fly, they have a strong heart and an efficient way of breathing; which are necessary for birds to fly.
