Pertanyaan

Read the text and answer the question! How do birds fly? Bird flight is one of the most remarkable phenomena in the animal kingdom, and it is not just a mere coincidence. Birds can fly because they havehollow bones that are very light and strong. Their lungs are very efficient and are designed to gather and store a good amount of oxygen to enable them to fly for very long distances without getting tired. Their feathers are also light, and the shape of their wings is perfect for catching the air. The fundamentals ofbirdflight are similar to those of aircraft, it needs a lift. When a bird is flying, its wings are flat so that the air flows easily around it in the direction the animal flies. As the air flows over the wing, the air flows faster over the top than the bottom because the wing is slightly curved on top. This means there will be more air on the bottom sidebecause the air is moving more slowly, sothe air pressure below the wings is higher creating the necessary lift needed for flying. Then, a bird wing slices in the air in the forward direction and gets pushed up from below. Getting the air to move over and under the wing also requires the wing to be moving. This is called thrust. Thrust is created when a bird flaps its wings using itsstrong breast muscles. Thus, as long as the bird keeps a sufficient amount of thrust and lift it will keep flying and increasing its speed until it decides to stop thrusting to glide or to make a stop. What do birds need to create the push to enable them to fly?