CBSE Class 9 Science Chapter 13: Why Do We Fall Ill NCERT Solutions

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NCERT Solutions PDF Class 9 PDF

This chapter delves into the fundamental concepts of health and disease, crucial for Class 9 Science students. The NCERT Solutions for 'Why Do We Fall Ill' explain the conditions necessary for maintaining good health, distinguishing between acute and chronic diseases, and understanding the various causes of illness. It also covers the importance of seeking medical attention for symptoms and the long-term health implications of different ailments. These solutions provide clear, step-by-step explanations and reasoning, helping students grasp the core ideas of disease prevention and management. They are an excellent resource for exam preparation, offering a comprehensive review of the chapter's key topics and reinforcing learning through detailed answers.

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BoardCBSE
ClassClass 9
SubjectScience
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 13: Why do We Fall ill

Chapter summary

Chapter 13, 'Why Do We Fall Ill,' focuses on defining health and disease. The NCERT Solutions cover the essential conditions for good health and freedom from disease, including personal and public hygiene, and proper nutrition. It differentiates between immediate and long-term health effects of various conditions and emphasizes the importance of consulting a doctor for symptoms. The solutions aim to build a foundational understanding of health, disease transmission, and prevention strategies.

Learning outcomes

  • Understand the definition and conditions for good health.
  • Identify the factors necessary to remain disease-free.
  • Differentiate between immediate and long-term health consequences of diseases.
  • Recognize the importance of seeking medical advice for health issues.
  • Explain the significance of hygiene and nutrition for well-being.

Topics covered

Paper topics

  • Definition of Health
  • Conditions for Good Health
  • Definition of Disease
  • Conditions for Being Free of Disease
  • Causes of Disease
  • Acute vs. Chronic Diseases
  • Symptoms of Illness
  • Importance of Medical Consultation
  • Long-term Health Effects
  • Hygiene and Nutrition

Important topics

  • Conditions for Good Health
  • Conditions for Being Free of Disease
  • Symptoms and Importance of Doctor Consultation
  • Long-term Effects of Diseases
  • Role of Hygiene and Nutrition

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Questions and Solutions

Question 1

State any two conditions essential for good health.
Solution: Health is defined as a state of complete physical, mental, and social well-being, not merely the absence of disease. Therefore, two essential conditions for maintaining good health are:
  1. Being free from diseases: This means the body's systems are functioning correctly without any pathological conditions.
  2. Social equality and harmony: Positive social interactions and a sense of belonging contribute significantly to mental and social well-being, which are integral parts of overall health.

Question 2

State any two conditions essential for being free of disease.
Solution: To be free from disease, certain conditions related to our environment and lifestyle are necessary:
  1. Avoiding causes of discomfort or disease: This involves maintaining personal hygiene (like washing hands regularly) and public cleanliness (like proper waste disposal and clean surroundings) to prevent exposure to pathogens and harmful agents. A good physical environment also plays a crucial role.
  2. Adequate Nutrition: Consuming a balanced and sufficient diet provides the body with the necessary nutrients for the proper functioning of cells and tissues, strengthening the immune system and enabling it to fight off potential infections.

Question 1

List any three symptoms that would make you think you are sick and ought to see a doctor. If only one of these symptoms were present, would you still go to the doctor? Explain why or why not.
Solution: Three common symptoms that indicate sickness and warrant a doctor's visit are:
  1. Headache
  2. Cough
  3. Loose motion
Yes, even if only one of these symptoms were present, it would be advisable to consult a doctor.

Reason: A single symptom can be the first sign of an underlying disease. Ignoring it or delaying medical attention could allow the condition to worsen. For instance, a persistent headache might be an early sign of a serious condition like meningitis, and prompt diagnosis and treatment are crucial for a better outcome.

Question 2

In which of the following cases do you think the long-term effects on your health are likely to be most unpleasant?
  1. If you get jaundice.
  2. If you get lice.
  3. If you get acne.
Why?
Solution: The case where the long-term effects on health are likely to be most unpleasant is:
  1. If you get jaundice.
Why: Jaundice is often a symptom of a more significant underlying issue affecting the liver. It is typically a chronic condition that requires a prolonged period for recovery. Unlike lice or acne, which are generally temporary and localized, jaundice affects the entire body's system, particularly the liver's function, and can lead to more severe and lasting health complications if not managed properly. The recovery process can be lengthy, impacting overall well-being for an extended duration.

Common mistakes

  • Underestimating the significance of single symptoms.
  • Not considering the long-term effects of diseases like jaundice.
  • Confusing personal hygiene with public health measures.

Revision tips

  • Focus on the definitions of health and disease provided.
  • List the conditions for good health and being disease-free.
  • Understand the difference between acute and chronic illness impacts.
  • Review the reasons for consulting a doctor, even with minor symptoms.

Practice MCQs

Q1. Which of the following is NOT a condition essential for good health?

Q2. What is a key factor for being free of disease, according to the solutions?

Q3. Which disease is mentioned as having potentially unpleasant long-term health effects?

Q4. Why is it important to see a doctor even with a single symptom like a headache?

Frequently asked questions

What are the two essential conditions for good health?

Two essential conditions for good health are being free from disease and having a state of well-being physically, mentally, and socially. This includes social equality and harmony.

What are the key factors to remain disease-free?

To remain disease-free, it is essential to stay away from the specific causes of illness by maintaining personal and public cleanliness, ensuring a good physical environment, and consuming proper and sufficient food for the body's functions.

Why is it important to see a doctor even if you have only one symptom?

Even a single symptom can be an indicator of a disease. Delaying a doctor's visit might allow the illness to progress, potentially leading to more serious health complications.

Which disease mentioned in the chapter has the most unpleasant long-term health effects?

Jaundice is considered to have the most unpleasant long-term health effects because it is a chronic disease that takes a long time to cure and affects the entire body.

How does social equality relate to health?

Social equality and harmony are essential for individual health, particularly for maintaining social and mental well-being, as stated in the context of good health conditions.

Important links

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