Pigeon
Explanation
Pneumatic bones are bones that contain air spaces connected to the respiratory system. Pigeons and other birds have pneumatic bones, which help reduce their overall body weight, facilitating flight. In contrast, mammals like rats (a) and humans (c) generally do not have pneumatic bones. Fish (d) typically have a swim bladder, an organ that helps control buoyancy, but it is not considered pneumatic in the same way as the bones in birds.
