NCERT Solutions for Class 9 Science Chapter 13 - Why Do We Fall ill

Aakash Institute’s NCERT Solutions for Class 9 Science Chapter 13, "Why Do We Fall Ill," provide clear answers to all exercises and questions in the NCERT textbook, aligned with the CBSE curriculum. These solutions are created by subject experts, offering reliable study material to help students prepare well and score high in exams.

The solutions use simple, easy-to-understand language, making it easier for Class 9 students to grasp key concepts. This method promotes active learning and strengthens understanding of the subject, aiding students in confidently tackling exam questions. The answers are carefully crafted to help students maximize their scores in CBSE exams.

Key topics in this chapter include understanding health, different types of diseases, causes of diseases, and the use of antibiotics. It also covers important principles of treatment and prevention. Through this chapter, students learn that health and disease are not isolated issues; they are deeply interconnected and influenced by various factors.

The chapter explains that cells are the basic building blocks of life, consisting of proteins, carbohydrates, fats, and more. These cells are constantly working, with complex reactions and repair processes taking place. Each organ in our body, like the heart, lungs, kidneys, and brain, performs unique and vital functions. Understanding how these functions contribute to our overall health helps students see the complexity of disease and the body's mechanisms to maintain well-being.

NCERT Solution Class 9 Science Chapter 13 Why Do We Fall Ill

Q1. State any two conditions essential for good health.

Answer: Two conditions essential for good health are:

(i) One should not have any disease.

(ii) One should have a clean and healthy environment around also hygienic food and clean water plays an important role.

Q2. State any two conditions essential for being free of disease.

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

(i) A proper and healthy diet is necessary.

(ii) Personal hygiene and cleanliness also play an important role.

Q3. Are the answers to the above questions necessarily the same or different? Why?

Answer:  No, the answers to the above questions need not be necessarily the same because disease-free is not the same as being healthy.

Both things are different. A person can have poor health without having any disease.

Topic 13.2 Disease and Its Cause

Q1. 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 why a person think that he or she is sick and ought to see a doctor are :

(i) Cough 

(ii) fever 

(iii) Headache

Even seeing one of these symptoms, I would go to the doctor. A single sign of disease on delay may cause serious illness.

Q 2. In which of the following cases 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: Jaundice can cause long-term effects on our health. It is a chronic disease and it takes a long time to be cured. It does not spread rapidly, it takes time to develop and time to get cured.

Topic 13.3 Infectious Diseases

Q1. Why are we normally advised to take bland and nourishing food when we are sick?

Answer: During illness our immune system becomes week. For the proper functioning of the immune system, easily digestible food is necessary for a sick person. Also, oil and fat- containing food are not good and could not be digested easily.

Q2. What are the different means by which infectious diseases are spread?

Answer: The infectious diseases are spread through the following means :

(i) Water: Disease like cholera is spread through contaminated water. 

(ii) Air: Common cold, pneumonia is spread through sneezing, coughing through the air.

(iii) Sexual contact: AIDS or syphilis is transmitted through sexual contact.

(iv) Animals: Some diseases like malaria, dengue are spread through mosquitoes.

Q3. What precautions can you take in your school to reduce the incidence of infectious diseases?

Answer: The precautions we can take in our school to reduce the incidence of infectious diseases can be like :

(i) Using a handkerchief while sneezing. 

(ii) Providing clean drinking water.

(iii) Preventing overcrowded classes.

(iv) Stay away from a diseased person.

Q4. What is immunization?

Answer: Protection of the body from communicable diseases by some agents that mimic agents.The introduction of some microbes into the body by vaccination to activate the immune system against a particular disease is known as immunization.

Q5. What are the immunization programmes available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area?

Answer: The immunization programs available at the nearest health centre in my locality are :

(i) Polio drops against polio.

(ii) DPT against Tetanus.

(iii) Vaccination against chickenpox. (iv)Vaccination against hepatitis.

(iv) Vaccination against measles.

The major health problems in my area are: Chickenpox, tetanus, hepatitis.

NCERT Solutions for Class 9 Science Chapter 13 Why Do We Fall Ill?: Solved Exercise Questions 

Q1. How many times did you fall ill in the last year? What were the illnesses?

(a) Think of one change you could make in your habits in order to avoid any of/most of the above illnesses.

(b) Think of one change you would wish for in your surroundings in order to avoid any of/most of the above illnesses .

Answer: This varies from person to person. Some people fall ill frequently and some don't even fall ill. It all depends on our diet, hygiene, and cleanliness also on our immune system.

Q2. A doctor/nurse/health-worker is exposed to more sick people than others in the community. Find out how she/he avoids getting sick herself/himself.

Answer: A doctor/nurse/health-worker is exposed to more sick people than others in the community. She/he avoids getting sick herself/himself by following some tips like:

(i) Using gloves and mask when in contact with a sick person.

(ii) Always drink clean water.

(iii) Ensure proper diet and hygiene all around.

(iv) Using sanitizers.

Q3. Conduct a survey in your neighborhood to find out what the three most common diseases are. Suggest three steps that could be taken by your local authorities to bring down the incidence of these diseases.

Answer: The three most common diseases are:

(i) Jaundice

(ii) Tuberculosis 

(iii)Typhoid

Steps to avoid these diseases are:

(i) Preventing mosquitoes from breeding. 

(ii) Drinking clean and safe water. (iii)Proper disposal of sewage.

Q4. A baby is not able to tell her/his caretakers that she/he is sick. What would help us to find out

(a) that the baby is sick? 

(b) what is the sickness?

Answer:

(a) The baby is sick if he /she is crying continuously and also can be noticed by behavior changes.

(b) The sickness can be determined by symptoms and noticing the body temperature of the baby.

Q5. Under which of the following conditions is a person most likely to fall sick?

(a) when she is recovering from malaria.

(b) when she has recovered from malaria and is taking care of someone suffering from chicken-pox.

(c) when she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox. Why?

Answer:

(c) A person is most likely to fall ill when she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox.

The reasons can be like :

(i) After malaria her immune system has become weak so for recovery she should take a healthy diet and in this situation, fasting is not acceptable.

(ii) Her immune system is weak and if she takes care of someone suffering from chickenpox then there is a high probability that she would also gain chickenpox.

Q6. Under which of the following conditions are you most likely to fall sick?

(a) when you are taking examinations.

(b) when you have traveled by bus and train for two days. (c) when your friend is suffering from measles. Why?

Answer: 

(c) When your friend is suffering from measles than you are most likely to fall sick

This is because measles is an infectious disease that spreads through nasal or throat discharge.

Why Do We Fall Ill Important Questions and Answers

Q1. What is health according to Class 9 Science?
Answer: Health refers to a state of complete physical, mental, and social well-being. It is not merely the absence of disease but the overall well-being of an individual, influenced by nutrition, hygiene, and living conditions. A healthy lifestyle is crucial for maintaining good health.

Q2. What are the main types of diseases discussed in this chapter?
Answer: Diseases are classified into infectious and non-infectious types. Infectious diseases spread from person to person through pathogens, like bacteria or viruses. Non-infectious diseases do not spread and can result from genetic factors, lifestyle choices, or environmental conditions, such as diabetes or heart disease.

Q3. What are the causes of infectious diseases?
Answer: Infectious diseases are caused by microorganisms like bacteria, viruses, fungi, and parasites. These pathogens enter the body through various means, such as air, water, physical contact, or infected animals. They disrupt normal bodily functions and can be transmitted from one individual to another.

Q4. How do antibiotics work to treat diseases?
Answer: Antibiotics are medicines that kill or inhibit the growth of bacteria, helping to treat bacterial infections. They work by targeting specific structures or functions in bacterial cells, like the cell wall. However, antibiotics do not work against viral infections, as viruses have a different structure.

Q5. What are the principles of disease prevention?
Answer: The principles of disease prevention include maintaining personal hygiene, ensuring clean drinking water, getting proper vaccinations, and promoting a healthy lifestyle. Preventive measures focus on reducing the chances of disease occurrence and controlling the spread of infections in a community.