Question

Mammalian lungs have an enormous number of minute alveoli (air sacs). This is to allow
A. More surface area for diffusion of gases
B. More space for increasing the volume of inspired air.
C. More nerve supply to keep the lungs working
D. More spongy texture for keeping lung in proper shape

Answer 1

The term alveolus (particular) alludes to an empty hole, bowl, or bowl in Latin. Subsequently, there are various sorts of alveoli (plural) found all through the human body. Be that as it may, alveoli are regularly used to depict the little air sacs of the lungs of warm-blooded creatures, and are accordingly referred to all the more explicitly as the pneumonic alveoli.

Complete answer:
Alveoli are a little sac-like structure that is liable for the trading of gases. They are the structure material of the lungs and all the oxygen and carbon dioxide change occur in the alveoli. Mammalian lungs have an enormous number of moment alveoli because it builds the surface territory for the dissemination of gases and consequently expands the proficiency of lungs.
In this way, the right choice is 'more surface region for the diffusion of gases'. So, option A is correct.
Oxygen atoms diffuse through a solitary cell in an alveolus and afterward a solitary cell in a hair-like to enter the circulatory system. Simultaneously, carbon dioxide particles, a result of cell respiration, are diffused once again into alveolus where they are removed out of the body through the nose or mouth.
Hence, option A is correct.

Note: Alveoli are the endpoint of the respiratory framework which begins when we breathe in the air into the mouth or nose. The oxygen-rich air goes down the windpipe and afterward into one of the two lungs using the privilege or left bronchus. From that point, the air is coordinated through more modest and more modest sections, called bronchioles, past the alveolar conduit, until it at long last enters an individual alveolus. Alveoli are lined by a fluid layer known as a surfactant which keeps up the shape and surface strain of the air sac. By keeping up the surface strain, there is more surface zone through which oxygen and $CO_2$ atoms can pass.