NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease

NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease

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CBSE Class 12th Exam Date:17 Feb' 26 - 17 Feb' 26

Irshad AnwarUpdated on 27 Oct 2025, 02:26 PM IST

The NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease discusses various forms of immunity. It includes innate and acquired immunity and how the immune system fights infections. Common diseases such as bacterial, viral, and fungal, and lifestyle diseases like cancer and drug addiction, are covered. The NCERT Solutions present the topics in a clear and organised way. This makes it easier for students to understand the concepts and score well in exams.

This Story also Contains

  1. Download Human Health and Disease Class 12 Questions and Answers PDF
  2. Get Class 12 Biology Chapter 7 Human Health and Disease Question Answer
  3. Approach to Solve Human Health and Disease Class 12 Question Answer
  4. Important Questions from Class 12 Biology Chapter 7 Human Health and Disease
  5. What Students Learn from Human Health and Disease NCERT Solutions
  6. Why Class 12 Biology Chapter 7 Human Health and Disease NCERT Solutions are Important?
  7. What Extra Should Students Study Beyond the NCERT for NEET?
  8. NCERT Solutions for Class 12 Biology Chapter-wise
NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease
NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease

Through the study of the Human Health and Disease Class 12 question answer, students can understand the cause of different diseases and how to protect themselves. The Human Health and Disease Class 12 Questions and Answers PDF is also important for NEET preparation, as it covers topics that are frequently asked in exams. The NCERT Solutions for Class 12 Biology provide explanations of all the questions in a step-by-step manner. For quick and easy revision, the solutions serve as a perfect resource to strengthen preparation and boost confidence before exams.

Download Human Health and Disease Class 12 Questions and Answers PDF

Students can download the PDF of the Human Health and Disease chapter from the link given below. The Human Health and Disease Class 12 Questions and Answers PDF includes answers to all the questions in a well-understandable manner.

Download PDF

Also Read,

Get Class 12 Biology Chapter 7 Human Health and Disease Question Answer

The detailed answers to all the questions of this chapter are given below. By going through the Class 12 Biology Chapter 7 Human Health and Disease question answers, which are prepared according to the latest NCERT guidelines, students can gain knowledge about diseases.

Ques1. What are the various public health measures that you would suggest as a safeguard against infectious diseases?

Answer:

To avoid infectious diseases, the following public health measures can be implemented:

  • Vaccination: Individuals should get vaccinated on time to prevent diseases such as cholera, tuberculosis, and hepatitis.
  • Awareness: All should be informed about diseases to safeguard themselves.
  • Sanitation: Maintaining the environment clean, consuming clean water, and having hygienic food can prevent diseases.
  • Vector Control: The disease-carrying insects and pests must be eradicated by destroying their breeding grounds.
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Ques 2. In which way has the study of biology helped us to control infectious diseases?

Answer:

The study of biology has contributed greatly to the prevention of diseases in various ways:

  • It makes us aware of the cause of diseases.
  • It helps in recognising how diseases are transmitted, e.g., if an individual develops diarrhoea, the infection can spread through dirty food or water.
  • It helps in discovering medicine for treating infected individuals.
  • It helps in the formulation of vaccines for preventing diseases

Ques 3. How does the transmission of each of the following diseases take place?

A) Amoebiasis

Answer:

Amoebiasis - It is transmitted through the consumption of water and food contaminated by amoebic cysts.

B) Malaria

Answer:

Malaria - It is transmitted from one person to another using the female Anopheles mosquito. When a female Anopheles mosquito bites an infected person, it ingests Plasmodium parasites with the blood. When it later bites a healthy person, the parasites are transmitted into their bloodstream.

C) Ascariasis

Answer:

Ascariasis - It is transmitted through food and water contaminated with eggs of the parasite.

D) Pneumonia

Answer:

Pneumonia - It transmits through droplet infection, i.e., through a sneeze, cough, sharing utensils, etc.

Ques 4. What measures would you take to prevent water-borne diseases?

Answer:

Waterborne diseases such as typhoid and cholera are prevented by:

  • Proper disposal of sewage and waste.
  • Periodic inspection and purification of water sources.
  • Drinking only purified and clean water.

Ques 5. Discuss with your teacher what 'a suitable gene' means in the context of DNA vaccines.

Answer:

A suitable gene is a unique segment of DNA that is implanted in the body to make certain proteins. These proteins protect the body against dangerous disease-producing organisms.

Ques 6. Name the primary and secondary lymphoid organs.

Answer:

Lymphoid organs help in making and activating immune cells:

  • Primary lymphoid organs: These are the bone marrow and thymus, where immune cells mature.
  • Secondary lymphoid organs: These are the spleen, lymph nodes, tonsils, Peyer's patches in the intestine, and the appendix, where immune cells encounter infections.

Ques 7: The following are some well-known abbreviations which have been used in this chapter. Expand well-known abbreviations

a) MALT

Answer:

MALT- Mucosal Associated Lymphoid Tissue

b) CMI

Answer:

CMI - Cell Mediated Immunity

c) AIDS

Answer:

AIDS- Acquired Immune Deficiency Syndrome

d) NACO

Answer:

NACO- National AIDS Control Organisation

e) HIV

Answer:

HIV- Human Immunodeficiency Virus

Ques8: Differentiate the following and give examples of each:

a) Innate and acquired immunity

Answer:

Innate Immunity
Acquired Immunity
Present from birth and provides general protection.Develops when the body is exposed to specific infections.
Acts as the first line of defenceActs as the second line of defence
Passed down genetically.Not inherited from parents.

Answer:

Active Immunity
Passive Immunity
The body produces its antibodies after infection or vaccination.Antibodies are given from an external source (e.g., injection).
Long-lasting protection.Short-term protection.
Takes time to develop.Works immediately.
Ques 9. Draw a well-labelled diagram of an antibody molecule.

Answer:

The well-labelled diagram of an antibody molecule is as follows:

antibody

Ques 10. What are the various routes by which transmission of the human immunodeficiency virus takes place?

Answer:

HIV is transmitted in various ways:

  • By sharing contaminated needles.
  • Through unprotected sex with an infected individual.
  • From an infected mother to her child during pregnancy.
  • Through transfusion of contaminated blood.

Ques 11. What is the mechanism by which the AIDS virus causes a deficiency of the immune system of the infected person?

Answer:

HIV causes a deficiency of the immune system in the following ways:

  • It binds to helper T-cells and injects its genetic material.
  • It utilises the machinery of the cell to make more copies of itself.
  • The infected T-cells burst, spilling more virus particles.
  • With time, the T-cells reduce in number, weakening the body against infections.

Ques 12. How is a cancerous cell different from a normal cell?

Answer:

Differences between cancerous cells and normal cells

Cancerous Cells
Normal Cells
Cancerous cells divide uncontrollably and may form tumours.Normal cells grow and divide in a regulated manner.
It can spread to other tissues and organsStay in one place and perform normal functions


Ques 13. Explain what is meant by metastasis.

Answer:

Metastasis is the condition in which cancer cells move from the primary location to other locations of the body through the blood or lymph. It is the terminal stage of cancer.

Ques 14. List the harmful effects caused by alcohol/drug abuse.

Answer:

Drug and alcohol abuse result in:

  • Weakening of body tissues and organs.
  • Heart issues are due to damage to the blood vessels.
  • Liver ailments such as cirrhosis.
  • Kidney failure due to overwork.
  • Infertility and other reproductive issues.
  • Damage to social life and family.
Ques 15. Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?

Answer:

Yes, peer pressure can result in drug or alcohol consumption. It can be prevented by:

  • Avoid individuals who consume drugs or alcohol.
  • Developing self-discipline and willpower.
  • Learning about the dangerous impacts of addiction.
  • Seeking support from parents or teachers.
  • Seeking proper medical assistance should depression or emotional distress become present.

Ques16. In your view, what motivates youngsters to turn to alcohol or drugs, and how can this be avoided?

Answer:

Teenagers can begin consuming alcohol or drugs because of:

  • Pressure from peers.
  • Desire for thrill and curiosity.
  • Stress, depression, or emotional issues.
  • Media pressure, wherein films and celebrities glorify alcohol and drug consumption.

Prevention is achieved through:

  • Speaking to youth about the risks of addiction.
  • Open conversations with teachers and parents.
  • Healthy stress management.
  • Positive role models and activities.

Ques 17. Why is it that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.

Answer:

After a person begins to take drugs or alcohol, it is hard to quit because:

  • The brain becomes habituated to the effects and longs for more.
  • With time, the body is unable to function normally without it.
  • Withdrawal symptoms such as anxiety, pain, and depression make quitting hard.
  • The individual can be socially dependent on alcohol or drugs.

NCERT Solutions for Class 12- Subject-wise

Approach to Solve Human Health and Disease Class 12 Question Answer

Below are a few steps that students can follow to solve the questions from this chapter easily.

  • Students first need to understand the difference between infectious and non-infectious diseases.

  • Different diseases like typhoid, pneumonia, malaria, and ascariasis should be studied in detail. Students can create flashcards using the Class 12 Biology Chapter 7 Human Health and Disease question answers.

  • The next step is to understand the concept of immunity, its types, antibodies, and the immune system. For a detailed explanation, students can use the Class 12 Biology Human Health and Disease question answer.

  • Students can prepare short notes by highlighting the symptoms and effects of different drugs, and how to control drug abuse.

  • Practice all types of questions given in the NCERT Solutions for Class 12 to understand the question pattern.

Also, check the NCERT Books and the NCERT Syllabus here:

Important Questions from Class 12 Biology Chapter 7 Human Health and Disease

The Human Health and Disease chapter helps students understand the causes of diseases and the importance of immunity. Given below are some of the important questions from this chapter. For more such questions, students can refer to the NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease. This improves their problem-solving skills and makes them familiar with the question pattern.

Question 1: Haemozoin is a

A. precursor of haemoglobin

B. The toxin released from Streptococcus-infected cells

C. The toxin released from Plasmodium-infected cells

D. The toxin released from Haemophilus-infected cells

Answer: The correct answer is option (C), the toxin released from Plasmodium-infected cells

Explanation:

A dangerous byproduct generated by the parasite Plasmodium in malaria disease is haemozoin, which is a by-product of the ingestion of haemoglobin by the parasitic red cell.

Question 2: Which of the following is not the causal organism for ringworm?

A. Microsporum

B. Trichophyton

C. Epidermophyton

D. Microsporum

Answer: The correct answer is option (D), Microsporum

Explanation:

Ringworm, a common fungal infection of the skin, is caused by dermatophytes belonging to genera such as Trichophyton, Microsporum, and Epidermophyton. Non-dermatophyte organisms, like bacteria or viruses, are not responsible for causing ringworm. Ringworm infections typically affect the skin, hair, and nails, presenting as red, itchy, circular rashes.

Question 3: A person with sickle cell anaemia is

A. more prone to malaria

B. more prone to typhoid

C. less prone to malaria

D. is less prone to typhoid

Answer: The correct answer is option (C), less prone to malaria

Explanation:

Patients suffering from sickle cell anaemia demonstrate a distinct kind of immunity against malaria due to the abnormally shaped RBCs. Since the parasite will find less favour in sickle-shaped RBCs, severe infection would occur less often. This protection is confirmed through multiple clinical research works, mainly from malaria-prone areas where this sickle cell trait has occurred as an intrinsic mechanism for defending against malaria.

Question 4: Antibodies present in colostrum, which protect the newborn from certain diseases, are of

A. IgG type

B. IgA type

C. IgD type

D. IgE type

Answer: The correct answer is option (B), IgA type

Explanation:

The antibodies present in colostrum, the first milk produced by mammals after birth, are primarily of the IgA (Immunoglobulin A) class. Colostrum is rich in these antibodies, which play a critical role in protecting the newborn from infections.

Question 5: Which of the following is not a lymphoid tissue?

A. Spleen

B. Tonsils

C. Pancreas

D. Thymus

Answer: The correct answer is option (C), Pancreas

Explanation:

The pancreas is not a lymphoid tissue. The pancreas is an exocrine and endocrine organ mainly functioning in digestion and the regulation of blood sugar levels. The spleen, tonsils, and thymus are all regarded as lymphoid tissues that have a function in the immune system. The lymphoid organs are responsible for the production and maturation of lymphocytes. These are considered critical in the initiation of immune responses.

NCERT Exemplar Class 12 Solutions

What Students Learn from Human Health and Disease NCERT Solutions

The chapter explains the significance of maintaining health and how various diseases affect living organisms.

  1. Students understand the causes, symptoms, and prevention of common diseases like typhoid, pneumonia, malaria, ascariasis, and filariasis.

  2. Through the Human Health and Disease Class 12 question answer, learners get explanations of the immune system, including innate and acquired immunity, and immunisation.

  3. The chapter highlights serious conditions like AIDS and cancer, explaining their causes, effects, and control measures.

  4. With the help of the Class 12 Biology Human Health and Disease question answer, students learn how drug and alcohol abuse impacts humans and society.

  5. Concepts like allergy, autoimmunity, and immunodeficiency are discussed to make students aware of immune system disorders.

Why Class 12 Biology Chapter 7 Human Health and Disease NCERT Solutions are Important?

The chapter Human Health and Disease focuses on the human immune system, common disease, their symptoms, and their prevention. The solutions for this chapter build a strong understanding of how the human body fights against infections.

  • Class 12 Biology Chapter 7 Human Health and Disease NCERT Solutions are important as they explain the types of immunity, such as innate and acquired.
  • The solutions provide a detailed explanation of common diseases such as malaria, typhoid, pneumonia, and AIDS, and how to prevent ourselves from them.
  • The structure and function of different types of antibodies are also included, which are commonly asked in the NEET and other competitive exams.
  • The solutions covered the topic of drug and alcohol abuse, which helps in quick revision, and students can score well in both theory and application-based questions.

What Extra Should Students Study Beyond the NCERT for NEET?

For better NEET preparation, students can explore some extra topics beyond the NCERT. The table below lists key areas to focus on. Along with this, students can refer to the NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease to avoid confusion.

Frequently Asked Questions (FAQs)

Q: What are the common diseases mentioned in Class 12 Biology Chapter 7?
A:

The NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease explain different diseases, such as bacterial, viral, protozoal, and fungal. A few of them are malaria, pneumonia, amoebiasis, typhoid, dengue, and HIV/AIDS.

Q: What are the causes and symptoms of AIDS?
A:

AIDS results from the HIV virus, which affects the immune system. The symptoms include weight loss, fever, tiredness, recurring infections, and inflamed lymph nodes.

Q: What is the role of interferons in immunity?
A:

Interferons are proteins that are released from cells as a response to viral infections. They protect surrounding cells from the virus and improve the immune system's response.

Q: What are the different types of immunity explained in NCERT Chapter 7?
A:

The chapter Human Health and Disease explains two types of immunity:

  • Innate Immunity – Natural immunity from birth.
  • Acquired Immunity – Gained over a period of time due to infection or vaccines.
Q: How do vaccines help in disease prevention?
A:

Vaccines are made of weakened or dead disease-causing germs. When they are put into the body, they make the immune system produce antibodies. This makes the body able to recognise and attack the infection in the future. 

Q: What are the key topics covered in NCERT Class 12 Biology Chapter 7?
A:

The important topics covered in the NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease are different types of diseases, immunity, vaccines, and the role of the immune system in fighting infections. It also discusses AIDS, cancer, drug abuse, and public health measures.

Q: Where can I find NCERT solutions for Class 12 Biology Chapter 7?
A:

Students can download the NCERT Solutions for Class 12 Biology Chapter 7 Human Health and Disease through the Careers360 page, which is

https://school.careers360.com/ncert/ncert-solutions-class-12-biology-chapter-7 

Q: How does the immune system fight infections?
A:

The immune system makes white blood cells and antibodies to fight and kill dangerous microorganisms. It also contains memory cells that enable it to recognise and combat the same infection if it re-enters the body.

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Questions related to CBSE Class 12th

On Question asked by student community

Have a question related to CBSE Class 12th ?

Hello,

Since you have passed 10th and 12th from Delhi and your residency is Delhi, but your domicile is UP, here’s how NEET counselling works:

1. Counselling Eligibility: For UP NEET counselling, your UP domicile makes you eligible, regardless of where your schooling was. You can participate in UP state counselling according to your NEET rank.

2. Delhi Counselling: For Delhi state quota, usually 10th/12th + residency matters. Since your school and residency are in Delhi, you might also be eligible for Delhi state quota, but it depends on specific state rules.

So, having a Delhi Aadhaar will not automatically reject you in UP counselling as long as you have a UP domicile certificate.

Hope you understand.

Hello,

You can access Free CBSE Mock tests from Careers360 app or website. You can get the mock test from this link : CBSE Class 12th Free Mock Tests

Hope it helps !

Yes, it is possible for a student who has done their 12th grade already to take upto 4 exams of their requirement. This is possible through the NIOS, NATIONAL INSTITUTE OF OPEN SCHOOLING. Get more info about the exam and the board through the following link.

https://school.careers360.com/exams/nios-class-12

For CBSE the PREVIOUS YEARS PAPERS can be accessed through the following link for the Concerned subjec by careers360.

https://school.careers360.com/boards/cbse/cbse-class-12-physics-last-5-years-question-papers-free-pdf-download

Consequently Careers360 does also have a chapter wise scheme of PYQs, you can access the STUDY MATERIAL (PYQs.) from the following link -

https://school.careers360.com/boards/cbse/cbse-question-bank

Thankyou.


Hello,

Sorry, but JoSAA does not accept marks from two different boards for the same qualification during counselling. However, you can use your NIOS marks to meet the JEE Main/Advanced eligibility criteria if they are better than your CBSE marks. You can use your NIOS marks for the eligibility check, but when presenting your documents, you may be required to present both marksheets and the one with the higher marks for each subject will be considered.

I hope it will clear your query!!