CBSE Questions for Class 9 Biology Why Do We Fall Ill Quiz 1 - MCQExams.com

• Health depends on three parameters - physical, mental, and social well-being. 
• According to WHO, health is a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity”
  

• A healthy body indicates both mental, social, and physical well-being. Health depends on three major factors physical, social, and mental. 
• Free of infection by pathogen sustains physical fitness and a stable mind provides mental fitness.
• Living in a polluted environment results in a higher risk of getting infected. 

• Many microbial agents can commonly move from an affected person to someone else in a variety of ways. Such disease-causing microbes can spread through the air. 
• This occurs through the little droplets thrown out by an infected person who sneezes or coughs. Someone standing close by can breathe in these droplets, and the microbes get a chance to start a new infection. 
• Examples of such diseases spread through the air are the common cold, pneumonia and tuberculosis. 
• Obviously, the more crowded our living conditions are, the more likely it is that such airborne diseases will spread.
• Cancer is non-communicable, AIDS spreads via body fluids, and cholera spreads through infected water.
• Hence the correct option is C.
  

$$\bullet$$ When an person infected with an air born pathogen, sneezing of this person release the pathogen containing droplet into air.

$$\bullet$$ Inhalation of this infected droplets by an healthy person, make them ill.

$$\bullet$$ This is a type of communicable disease i.e. transmitted from one person to next.

$$\bullet$$ High blood pressure, genetic abnormalities and blood cancer all are non- communicable disorder, so this disease can not be transmitted from one person to another.

• Edward Jenner was an English doctor, who found that vaccination with cowpox can protect individuals from smallpox. 
• He is well known for his contribution to the immunization and eradication of smallpox. 
• Jenner's work is widely regarded as the foundation of immunology and known as the father of immunology.