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


Under which of the following conditions are you most likely to fall sick?
  1. when you are taking examinations.
  2. when you have travelled by bus and train for two days.
  3. when your friend is suffering from measles.


c. You are most likely to fall sick when you will be in the company of your friend who is suffering from measles.

Measles is a highly contagious disease that spreads through droplets from the nose or mouth of the infected person. Therefore, if your friend is suffering from measles, you should stay away from him/her to protect yourself from the disease.


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.


The three most common diseases are:

  1. Malaria
  2. Jaundice
  3. Typhoid

Steps that should be taken by the local authorities to bring down the incidence of these diseases:

  1. Avoid collection of  stagnant water in the surroundings to prevent mosquitoes from breeding
  2. Ensuring the supply of clean drinking water
  3. Managing the proper disposal of sewage and waste to check the breeding ground of germs or causative agents of various diseases


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?


A doctor/nurse/health-workers, generally, take the following precautions:

  1. They wear a mask while treating the infected person.
  2. They keep themselves covered while moving around an infected area. 
  3. They eat healthy and nutritious food and drink lots of clean water.
  4. They give importance to personal and community hygiene.


How many times did you fall ill in the last one year? What were the illnesses?
  1. Think of one change you could make in your habits in order to avoid any of/most of the above illnesses.
  2. Think of one change you would wish for in your surroundings in order to avoid any of /most of the above illnesses.


Frequency of falling ill varies from person to person. It depends on personal factors such as the immunity of a person and environmental factors such as cleanliness in the surrounding in which he/she is living. Some of the common diseases from which generally children get affected are cold, cough, fever, stomach infection, dengue, malaria, typhoid, etc.

  1. To avoid most of the above mentioned illnesses a person should have healthy eating habits. He/she should eat balanced diet that would help in his/her growth and development. A person should include lots of fruits in his diet as fruits boost up our immune system and provide minerals and vitamins that protect us from many diseases. 
  2. To avoid the spread of diseases like dengue, malaria, etc, one has to keep his surroundings clean so that the germs causing these diseases would not get a chance to grow and multiply. By doing so one can stop the diseases like dengue, malaria, typhoid, etc.


Under which of the following conditions is a person most likely to fall sick?
  1. when she is recovering from malaria.
  2. when she has recovered from malaria and is taking care of someone suffering from chicken pox.
  3. when she is on a four day fast after recovering from malaria and is taking care of someone suffering from chicken pox.


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

Fasting just after the recovery from malaria would definitely weaken the immune system of the person and would not even help her to fight with any infection if she comes in contact with it. Under these conditions, if she takes care of someone who is suffering from chicken pox, she is more likely to get infected from chicken pox and will fall sick.


A baby is not able to tell her/his caretakers that she/he is sick. What would help us to find out
  1. that the baby is sick?
  2. what is the sickness?


  1. Following behavioural changes in the baby would help us to find out that the baby is sick:
  1. Constant crying of the baby,
  2. Avoiding his/her meal
  3. Mood swings in the baby
  1. The sickness in a baby can be identified by the following symptoms or indications:
  1. vomiting
  2. fever
  3. loose motions
  4. dullness in activity

Benefits of NCERT Solutions

Following are some of the benefits of using NCERT Solutions by Extramarks.

1. They are developed by our experts with the right approach for precisely answering the textbook questions.

2. They are free of cost and available online to help class 9 students.

3. They not only explain every topic but also prepare students for further examinations. 

4. They are proven to be helpful to students in their exam preparation, homework and competitive exams.

5. They will help in understanding the solutions and the methodology of writing the answers in the exams.

Tips & Strategies for Class 9 Exam Preparation

1. Jot down important chapters or topics for your exam preparation.

2. Learn from the best teachers with Extramarks and clear your doubts instantly.

3. While practicing, refer to NCERT Solutions for class 9 to understand step-by-step solutions to all questions.

4. Solve as many sample papers as you can to prepare well for the exams.

5. Lastly, don’t panic. Try to meditate at least for 15 minutes every day- it will help you retain things better.

Why opt for Extramarks NCERT Solutions for Class 9 ?

Extramarks provide NCERT Solutions for all subjects at your fingertips. These solutions are designed by subject matter experts and provide solutions to every NCERT textbook questions. These solutions help students in their exam preparation and home assignments. We hope NCERT Solutions for class 9 will come in handy for every student and help them understand everything in a better way.

Frequently Asked Questions

When to refer to NCERT Solutions for Class 9?

You can refer to NCERT solutions for class 9 anytime during your academic year. Whether you are preparing for class tests or unit tests or pre-board exams, you can refer to the class 9 NCERT solutions easily. The NCERT solutions are available on Extramarks - The Learning App and Extramarks website in the footer section.

What can I do to get better marks in Class 9?

If you want to gain good marks in Class 9 examination then we suggest that you go through NCERT books solutions for class 9 listed on the Extramarks website. The solutions are self-explanatory and written in easy to understand language so you can easily learn and ace your exams with the help of these solutions.

Why are the NCERT solutions Important for Class 9?

NCERT solutions class 9 are self-explanatory and form the basis of examination. Since the exam syllabus is taken directly out of the NCERT books, studying NCERT solutions becomes important to prepare for the exams.

What are some expert tips to score good marks in Class 9 CBSE?

If you want to score good marks in Class 9, follow these tips:

1. Study NCERT Solutions from Extramarks website.

2. Study using Extramarks - The Learning App, practice using the sample papers, and prepare through the interactive video modules.

3. Prepare a timetable and schedule your subjects and save time for revision.. Get concept clarity by tuning in to the Extramarks live classes.

How to Prepare for Competitive Exam Through NCERT Class 9 Solutions?

NCERT solutions for Class 9 science are amazingly useful for JEE and NEET and if you are preparing for any other competitive exam then consider studying through the NCERT solutions listed on the Extramarks website. You can also study the 9-10 and other classes syllabus on Extramarks - The Learning App.

Start Your
7-Days Free Trial
and experience it yourself
Start Trial
Play StoreApp Store
Flying Girl
A subscription
that’s worth your
Get the best classroom experience on
India’s leading learning platform

in touch

Have a query about our services?
Get in touch with us and we will
guide you through a new world of
redefined learning