NCERT Solutions for Class 9 Science Chapter 13 Why Do We Fall Ill?

In-Text Questions-Answer Solved

NCERT Book for Class 9 Science Page 178

1. State any two conditions essential for good health.

Answer:- Two conditions essential for good health are:

  1. State of Complete physical, mental and social well-being.
  2. Good social and economical condition.

2. State any two conditions essential for being free of disease.

Answer:- Two conditions essential for being free of disease:-

Personal,community and domestic hygiene.

Getting pre- vaccination and proper medicines whenever required.

3. Are the answers to the above questions necessarily the same or different? Why?

Answer:- The answers to the above questions are same to some extent but they are actually very different. Because being free of diseases means that the person is physically fit but for having good health a person should be physically as well as mentally and socially well.

NCERT Book for Class 9 Science Page 180

1.List any three reasons why you would think that you are sick and ought to see a doctor. If only one

of these symptoms were present, would you still go to the doctor? Why or why not?

Answer:- The three reasons we would think that we are sick and ought to see a doctor are following:-

  1. Headache
  2. Fever
  3. Cough and cold

We generally not go to the doctor if only one of these symptoms were present because it does not affect the general health or the ability to work. But if these symptoms last for a long period then we would definitely visit the doctor.

 

2.In which of the following case do you think the long-term effects on your health are likely to be most unpleasant?

  • if you get jaundice,
  • if you get lice,
  • if you get acne.

Why?

Answer:- From the above mentioned cases getting lice and acne are acute problem and can be cured easily without any serious effects on our health. But jaundice is a chronic disease and it can harm our liver badly, its long term effects on our health can be fatal.

 

NCERT Book for Class 9 Science Page 187

 

1. Why are we normally advised to take bland and nourishing food when we are sick?

Answer:- The  bland and nourishing food  provides nutrients to our body that further provides energy and make new cells. No spices in the food makes its digestion process faster. It does not release acids that can interfere in the treatment and cure.

 

2. What are the different means by which infectious diseases are spread?

Answer:- The different means by which infectious diseases spread are following:

  1.  Through air: Such diseases are called air-borne diseases. Example- common cold, influenza, tuberculosis etc.
  2.  Through food and water: Contaminated food or water, that contains bacteria, virus, etc. can cause diseases like cholera typhoid, hepatitis.
  3.  Through contact: Many diseases can be spread by the contact of infected person with the healthy person. Example, fungal infections, skin diseases, scabies etc.
  4.  By sexual contact: Diseases like syphilis, AIDS can be transmitted through sexual contact.
  5.  By body fluids: Infected fluids of human body for example- blood, semen, mother’s milk, can also cause disease like AIDS.
  6.  By Vectors: Disease can be spread through vector by carrying pathogens from one place to another. Example, mosquitoes are vectors that carry pathogens like protozoa.