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

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The NCERT Solutions for Class 9 Science Chapter 13 Why Do We Fall Ill? have been included in this article. Class 9 Science Chapter 13 Why Do We Fall Ill has the following important concepts:

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NCERT Solutions for Class 9 Science Chapter 13

Important Topics for Class 9 Science Chapter 13 Why Do We Fall Ill?

Why do we fall ill? or What causes diseases? These questions cannot be answered in one line. There can be various reasons for falling sick such as lack of personal hygiene, extreme exposure to intense weather, and eating unhealthy foods. An unhealthy lifestyle can also be one of the major reasons for bad health and sickness.

Immune System

The immune system in the human body helps prevent protracting diseases. In simple words, it protects our body from foreign invaders, including germs like bacteria, viruses, fungi, and toxins.

The human immune system includes:

Lymphoid Organs
Immune Cells
Soluble Molecules (Antibodies)
Lymphoid Tissues

Types of Diseases

Disease is any condition responsible to impair or worsen good health of any organism, including humans. Diseases interfere with the normal functioning the body has, gradually worseing it.

Diseases can be divided into two segments:

Acute Diseases
Chronic Diseases

Pathogens

A pathogen is any organism, including microbes, that can produce disease. It can simply be defined as an infectious agent, or a germ.

Pathogens are of different kinds:

Algae
Bacteria
Virus
Parasites
Fungi
Prion
Viroid

Also Check:

Chapter Related Links
Difference between Vaccination and Immunization	Difference Between Antigen And Pathogen	Human Health and Diseases
Vaccination	Human Diseases	Human Bacterial Diseases
Mumps	Chronic Disease and Poor Health	Diseases MCQs
Viral Diseases	MCQs on Human Health and Diseases

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CBSE X Related Questions

1.
Identify the part that controls the closing and opening of the stomatal pore in leaves of plants. Select the correct option.
- Stomata
- Epidermal cells
- Guard cells
- Chloroplasts
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2.
Assertion (A): Reflex actions do not involve thinking.
Reason (R): Most reflex actions are controlled by the spinal cord.
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
View Solution
3.
Due to change in length and area of cross-section of a conductor, resistance of conductor changes while resistivity does not change. Why ?
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4.
(a) Study the given electric circuit in which 2 A electric current is flowing between points X and Y.

(i) Using the battery, key, voltmeter and ammeter in this given electric circuit, redraw a circuit diagram in which 2 \(\Omega\) and 4 \(\Omega\) resistors are connected between X and Y in parallel combination.
(ii) Circuit drawn by you, in which resistors are connected in parallel combination, calculate the electric current flowing through 4 \(\Omega\) resistor.
View Solution
5.
Give one example each of electrolytic decomposition and decomposition by sunlight.
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6.
How many bulbs of resistance \( 8 \ \Omega \) each should be connected in parallel combination to draw a current of \( 2 \text{ A} \) from a battery of \( 4 \text{ V} \) ?
View Solution

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

NCERT Solutions for Class 9 Science Chapter 13