Chapter 8: Human Health and Disease – Very Short Answer Type Questions

CBSE Class 12 Biology Very Short Answer Questions (NCERT): Human Health and Disease

Course & Examination Details

Course: CBSE Class 12 Biology
Unit: Unit III – Biology and Human Welfare
Chapter: Chapter 8 – Human Health and Disease
Prescribed Textbook: NCERT Biology Class XII
Examination: CBSE Class 12 Board Examination
Question Type: Very Short Answer Type (VSA)
Answer Length: 20–30 words each

Section A: Health and Its Significance

Q1. Define health according to WHO.

Answer: Health is a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.

Q2. Mention two factors that affect human health.

Answer: Genetic factors and environmental conditions such as hygiene, nutrition, and lifestyle significantly affect human health.

Q3. What is meant by disease?

Answer: Disease is a condition that disturbs the normal physiological functioning of the body, leading to discomfort or illness.

Q4. Differentiate between congenital and acquired diseases.

Answer: Congenital diseases are present at birth, whereas acquired diseases develop after birth due to infection or lifestyle factors.

Q5. Why is health considered a social issue?

Answer: Health depends on sanitation, nutrition, education, and economic conditions, which are influenced by social environment.

Section B: Common Human Diseases

Q6. Name the causative agent of typhoid.

Answer: Typhoid is caused by the bacterium Salmonella typhi.

Q7. How is pneumonia transmitted?

Answer: Pneumonia is transmitted through inhalation of droplets released by coughing or sneezing of an infected person.

Q8. Name the pathogen responsible for malaria.

Answer: Malaria is caused by the protozoan parasite Plasmodium.

Q9. Which mosquito transmits malaria?

Answer: Female Anopheles mosquito transmits malaria.

Q10. What causes amoebiasis?

Answer: Amoebiasis is caused by the protozoan Entamoeba histolytica.

Section C: Pathogens and Parasites

Q11. What are pathogens?

Answer: Pathogens are disease-causing organisms such as bacteria, viruses, protozoa, fungi, and helminths.

Q12. Name one viral disease in humans.

Answer: AIDS is a viral disease caused by Human Immunodeficiency Virus (HIV).

Q13. What is a parasite?

Answer: A parasite is an organism that lives in or on another organism and derives nutrition at the host’s expense.

Q14. Differentiate between ectoparasite and endoparasite.

Answer: Ectoparasites live on the host’s surface, while endoparasites live inside the host’s body.

Q15. Name one disease caused by helminths.

Answer: Ascariasis is a disease caused by the helminth Ascaris lumbricoides.

Section D: Immunity

Q16. Define immunity.

Answer: Immunity is the ability of the body to resist and fight against disease-causing pathogens.

Q17. What is innate immunity?

Answer: Innate immunity is non-specific defence present from birth that provides immediate protection against pathogens.

Q18. Name any two physical barriers of innate immunity.

Answer: Skin and mucous membranes are physical barriers of innate immunity.

Q19. What is acquired immunity?

Answer: Acquired immunity is pathogen-specific immunity developed after exposure to an antigen and shows memory.

Q20. Name the cells responsible for acquired immunity.

Answer: B-lymphocytes and T-lymphocytes are responsible for acquired immunity.

Section E: Types of Acquired Immunity

Q21. What is active immunity?

Answer: Active immunity develops when the body produces its own antibodies in response to infection or vaccination.

Q22. What is passive immunity?

Answer: Passive immunity is obtained by transfer of ready-made antibodies and provides immediate but short-term protection.

Q23. Give one example of natural passive immunity.

Answer: Antibodies transferred from mother to child through placenta or colostrum provide natural passive immunity.

Q24. Why is active immunity long-lasting?

Answer: Active immunity is long-lasting due to formation of memory cells during immune response.

Q25. What is an antigen?

Answer: An antigen is a foreign substance that induces an immune response in the body.

Section F: Vaccination

Q26. What is vaccination?

Answer: Vaccination is the administration of antigenic material to stimulate immunity without causing disease.

Q27. Name one live attenuated vaccine.

Answer: BCG vaccine is a live attenuated vaccine.

Q28. How do vaccines work?

Answer: Vaccines stimulate the immune system to produce antibodies and memory cells against specific pathogens.

Q29. What is herd immunity?

Answer: Herd immunity occurs when a large population becomes immune, reducing disease spread.

Q30. Name one recombinant vaccine.

Answer: Hepatitis B vaccine is a recombinant vaccine.

Section G: Allergies

Q31. What is an allergy?

Answer: Allergy is an exaggerated immune response to harmless substances called allergens.

Q32. Name two common allergens.

Answer: Pollen and dust mites are common allergens.

Q33. Which antibody is involved in allergy?

Answer: IgE antibody is involved in allergic reactions.

Q34. What chemical causes allergic symptoms?

Answer: Histamine released from mast cells causes allergic symptoms.

Q35. Name one symptom of allergy.

Answer: Sneezing, watery eyes, or skin rashes are common allergy symptoms.

Section H: Autoimmune Diseases

Q36. What is an autoimmune disease?

Answer: Autoimmune disease occurs when the immune system attacks the body’s own tissues.

Q37. Name one autoimmune disease.

Answer: Rheumatoid arthritis is an autoimmune disease.

Q38. What causes autoimmune diseases?

Answer: Breakdown of self-tolerance due to genetic and environmental factors causes autoimmune diseases.

Q39. Is immunity helpful in autoimmune diseases?

Answer: No, immunity becomes harmful as it targets self-antigens.

Q40. Name another autoimmune disorder mentioned in NCERT.

Answer: Type 1 diabetes is an autoimmune disorder.

Section I: Drugs and Alcohol Abuse

Q41. What are drugs?

Answer: Drugs are chemical substances that alter brain function and behaviour when consumed.

Q42. Name one narcotic drug.

Answer: Heroin is a narcotic drug.

Q43. What type of drug is alcohol?

Answer: Alcohol is a central nervous system depressant.

Q44. Name one harmful effect of alcohol abuse.

Answer: Alcohol abuse can cause liver cirrhosis and impaired judgment.

Q45. What is drug addiction?

Answer: Drug addiction is a physical or psychological dependence on drugs.

Section J: Prevention and Awareness

Q46. Mention one reason for drug abuse among adolescents.

Answer: Peer pressure is a major reason for drug abuse among adolescents.

Q47. How can drug abuse be prevented?

Answer: Education, counselling, family support, and awareness programmes help prevent drug abuse.

Q48. Why is sharing needles dangerous?

Answer: Sharing needles increases risk of HIV and hepatitis transmission.

Q49. Name one preventive measure against infectious diseases.

Answer: Vaccination and maintaining personal hygiene help prevent infectious diseases.

Q50. Why is awareness important in maintaining health?

Answer: Awareness promotes healthy habits, disease prevention, and responsible lifestyle choices.