Explanation

Explanation

Alveoli:

Bronchioles terminate in tiny air sacs called alveoli.

These are the primary sites for gas exchange in the lungs. 

Alveolar sac:

Alveoli are clustered together to form alveolar sacs.

These sacs are the functional units of the lung where oxygen and carbon dioxide exchange occurs. 

Explanation

Efficient gas exchange requires a rich blood supply to transport oxygen and carbon dioxide.

Along with being thin, moist, and having a large surface area, blood flow ensures rapid diffusion.

Explanation

In a reversible process, the entropy of the system remains constant. 

 A key characteristic of a reversible process is that it can be reversed without leaving any net change in the system or its surroundings, including the entropy. 

Explanation

A gas being cooled is a system where entropy is decreasing. 

When a gas is cooled, its molecules slow down and become more ordered, leading to a decrease in entropy. 

Explanation

The main function of the respiratory system is to supply oxygen to the body.

It also removes carbon dioxide through the process of gas exchange.

Explanation

Emphysema is caused by damage and breakdown of alveolar walls, often due to smoking.

It reduces surface area for gas exchange, leading to breathing difficulties.

Explanation

The bacteria that cause tuberculosis and leprosy are Mycobacterium tuberculosis and Mycobacterium leprae.

So the correct answer is d) None of these

Explanation

 Hepatitis A is primarily spread through contaminated food or water that has been in contact with infected feces, meaning it's transmitted through the fecal-oral route. 

Explanation

Mycoplasma is a type of bacteria, not a virus.

It lacks a cell wall, which makes it resistant to certain antibiotics.

Bacteria are capable of independent replication, unlike viruses which need a host cell. 

SARS, FIV, and HIV are all viruses:

SARS stands for Severe Acute Respiratory Syndrome,

FIV for Feline Immunodeficiency Virus,

HIV for Human Immunodeficiency Virus.

These are all viruses that infect specific hosts and require a host cell to replicate their genetic material.