Air sacs are present in

Air sacs are present in poultry, which includes birds like chickens, ducks, and turkeys. These air sacs are an essential part of the avian respiratory system. Unlike mammals, birds have a unique respiratory system that includes a series of air sacs that facilitate a continuous flow of air through their lungs. This system allows for more efficient gas exchange, which is crucial for their energy needs during activities like flying.

In more detail, when birds inhale, air doesn't just go into their lungs but also fills these air sacs. On the next exhalation, the air moves from the air sacs into the lungs, where oxygen is exchanged for carbon dioxide. This method ensures that the bird's lungs have a continuous supply of fresh air, both when they inhale and exhale.

Other animals listed, such as rabbits, goats, and cattle, have different respiratory systems without air sacs; they rely on diaphragm-based breathing similar to humans for their oxygen needs. The specialized respiratory system of birds thus gives them an advantage in terms of metabolic efficiency, which is particularly important given the energy demands of flying.