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

Read Also:

Important Science Study Guides
Difference between in physics	Physics Constants	Difference between in biology
Difference between in chemistry	Named Reactions	Periodic Table

CBSE X Related Questions

1.
(i) \( \text{AgNO}_3 + \text{NaCl} \rightarrow \text{NaNO}_3 + \text{AgCl} \)
(ii) \( \text{K}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + 2\text{KCl} \)
Which of the following options clearly describes both the reactions?

(i) is double displacement, (ii) is displacement reaction.
Both, (i) and (ii) are displacement reactions and precipitation reactions.
Both, (i) and (ii) are double displacement reactions and precipitation reactions.
(i) is displacement, (ii) is double displacement reaction.

View Solution

2.
Assertion : Bacteria produced as a result of asexual reproduction would be similar. Reason (R): There would be only minor differences between the bacteria generated due to small inaccuracies in DNA replication.

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.
The natural sources of oxalic acid, lactic acid and methanoic acid respectively are:

tomato, curd, ant-sting
tomato, orange, nettle-sting
orange, milk, ant-sting
orange, sour milk, nettle-sting

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4.
Assertion (A): Carbon shares its valence electrons with other atoms of carbon or with atoms of other elements.
Reason (R): The shared electrons belong to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.

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

5.
Assertion : In human beings, the respiratory pigment is haemoglobin present in red blood cells.
Reason (R) : Haemoglobin has a very high affinity for carbon dioxide.

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

6.
The gases evolved on heating lead (II) nitrate crystals are :

NO and \( O_2 \uparrow \)
\( N_2 \) and \( NO_2 \)
\( NO_2 \) and \( H_2 \)
\( NO_2 \) and \( O_2 \)

View Solution

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

NCERT Solutions for Class 9 Science Chapter 13

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

Immune System

Types of Diseases

Pathogens

CBSE X Related Questions

1.
(i) \( \text{AgNO}_3 + \text{NaCl} \rightarrow \text{NaNO}_3 + \text{AgCl} \)
(ii) \( \text{K}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + 2\text{KCl} \)
Which of the following options clearly describes both the reactions?

2.
Assertion : Bacteria produced as a result of asexual reproduction would be similar. Reason (R): There would be only minor differences between the bacteria generated due to small inaccuracies in DNA replication.

3.
The natural sources of oxalic acid, lactic acid and methanoic acid respectively are:

4.
Assertion (A): Carbon shares its valence electrons with other atoms of carbon or with atoms of other elements.
Reason (R): The shared electrons belong to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.

5.
Assertion : In human beings, the respiratory pigment is haemoglobin present in red blood cells.
Reason (R) : Haemoglobin has a very high affinity for carbon dioxide.

6.
The gases evolved on heating lead (II) nitrate crystals are :

Similar Science Concepts

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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

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

Immune System

Types of Diseases

Pathogens

CBSE X Related Questions

1.(i) \( \text{AgNO}_3 + \text{NaCl} \rightarrow \text{NaNO}_3 + \text{AgCl} \) (ii) \( \text{K}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + 2\text{KCl} \) Which of the following options clearly describes both the reactions?

2.Assertion : Bacteria produced as a result of asexual reproduction would be similar. Reason (R): There would be only minor differences between the bacteria generated due to small inaccuracies in DNA replication.

3.The natural sources of oxalic acid, lactic acid and methanoic acid respectively are:

4.Assertion (A): Carbon shares its valence electrons with other atoms of carbon or with atoms of other elements. Reason (R): The shared electrons belong to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.

5.Assertion : In human beings, the respiratory pigment is haemoglobin present in red blood cells. Reason (R) : Haemoglobin has a very high affinity for carbon dioxide.

6.The gases evolved on heating lead (II) nitrate crystals are :

Similar Science Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
(i) \( \text{AgNO}_3 + \text{NaCl} \rightarrow \text{NaNO}_3 + \text{AgCl} \)
(ii) \( \text{K}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + 2\text{KCl} \)
Which of the following options clearly describes both the reactions?

2.
Assertion : Bacteria produced as a result of asexual reproduction would be similar. Reason (R): There would be only minor differences between the bacteria generated due to small inaccuracies in DNA replication.

3.
The natural sources of oxalic acid, lactic acid and methanoic acid respectively are:

4.
Assertion (A): Carbon shares its valence electrons with other atoms of carbon or with atoms of other elements.
Reason (R): The shared electrons belong to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.

5.
Assertion : In human beings, the respiratory pigment is haemoglobin present in red blood cells.
Reason (R) : Haemoglobin has a very high affinity for carbon dioxide.

6.
The gases evolved on heating lead (II) nitrate crystals are :