Question

Vertebrates having air sacs are
A. Birds
B. Amphibians
C. Reptiles
D. Mammals

Answer 1

Hint:- Air sacs are the open space in which air is filled. Air sacs are found in certain vertebrates. These are tiny sacs found in insects, birds and other vertebrates. Air sacs help in flight. Air sacs increase efficiency of respiratory organs of the organisms. Hollow bones are present in birds which act as air cavities. Air sacs are also known as bird’s respiratory systems.

Complete answer:
Air sacs are the internal compartment filled with air to facilitate internal air. Vertebrates have air sacs present in different body parts & perform various functions. Air sacs provide large surface area for gaseous exchange and increase the respiratory efficiency of the organism. Birds have most air sacs. Aerosteon, have many air sacs in the body and they are identified as a more primitive form of modern bird airways.
Earlier air sacs were regarded as weight-saving devices but later these are known as bird’s respiratory systems. Due to this feature, the weight of birds is less which helps them to fly.
Tidal volume estimation can be made and tells more about this functioning in vertebrates. Efficiency and oxygen exchange capacity increases with the help of internal compartments (air sacs) present in birds. Air sacs fold air and facilitate internal air passage. It also provides continuous flow of large volumes of air through the lungs. From the above information we can say that birds are the vertebrates having air sacs. So, the correct answer is option A.

Note:- Respiratory system of avian is very different from other vertebrates. This system also plays a very important role in thermoregulation maintaining normal body temperature. Birds have small lungs but they have nine air sacs which help them in respiration. Unidirectional flow of air is observed which means that air moves through bird lungs is largely fresh air and has higher oxygen content. In mammals flow of air is bidirectional.