Home › Free notes › Class 8 Science › Health: The Ultimate Treasure

Health: The Ultimate Treasure – Class 8 Science notes, important questions and MCQs

NCERT Class 8 Science, chapter 3. Notes, key terms, important questions with answers and MCQs.

Chapter overview

Health is physical, mental and social well-being. Balanced food, hygiene, exercise, rest and vaccination prevent many diseases.

Diseases

Communicable diseases spread by germs through air, water, food, insects or contact (TB, cholera, dengue).
Non-communicable diseases do not spread from person to person (diabetes, heart disease).
Deficiency diseases come from lack of nutrients (scurvy – vitamin C, anaemia – iron, goitre – iodine).

Staying healthy

Balanced diet with carbohydrates, proteins, fats, vitamins, minerals, fibre and water.
Clean drinking water, washing hands, covering food, mosquito control.
Vaccines (BCG for TB, polio drops) build immunity; adolescents need extra iron and protein.

Key terms

Immunity: the body's ability to fight germs
Communicable disease: disease that spreads from one person to another
Vaccine: weakened or killed germs or parts given to build immunity

Formulas

Dengue and malaria are spread by mosquitoes (Aedes and Anopheles)

Important questions with answers

What is the difference between communicable and non-communicable diseases? Give one example each.2 marks

Communicable diseases spread from person to person through germs (tuberculosis, COVID-19). Non-communicable diseases do not spread from others (diabetes, heart disease).

How do mosquitoes spread malaria and dengue? Give two preventive steps.3 marks

Mosquitoes carry the germ from an infected person and inject it while biting another person: Anopheles spreads malaria, Aedes spreads dengue. Prevention: do not let water collect in coolers, pots or tyres; use nets, repellents and full-sleeve clothes.

Explain how the body fights disease (immunity) and describe five habits for good health.5 marks

Skin and mucus form the first barrier. If germs enter, white blood cells attack them and make antibodies; after recovery or vaccination, the body remembers the germ and fights it quickly next time. Healthy habits: balanced diet; regular exercise and play; enough sleep; washing hands with soap and drinking clean water; getting all vaccines on time (also staying away from tobacco and managing stress by talking to trusted people).

Quick revision

Health = body + mind + social well-being.
Iron deficiency causes anaemia.
BCG vaccine protects against tuberculosis.

Exam tips

Learn "deficiency → disease" pairs; they are very common MCQs.
Stagnant water breeds mosquitoes — remove it to prevent dengue and malaria.

Practice MCQs

Lack of vitamin C causes
1. rickets
2. anaemia
3. goitre
4. scurvy
Show answer
Answer: (d) scurvy. Scurvy.
Dengue is spread by
1. housefly
2. Aedes mosquito
3. cockroach
4. rat
Show answer
Answer: (b) Aedes mosquito. Aedes.
Which is a non-communicable disease?
1. tuberculosis
2. diabetes
3. cholera
4. chickenpox
Show answer
Answer: (b) diabetes. It does not spread by germs.
Anaemia is caused by lack of
1. iodine
2. calcium
3. iron
4. vitamin A
Show answer
Answer: (c) iron. Iron is needed for haemoglobin.
Which disease spreads through contaminated water
1. malaria
2. dengue
3. tuberculosis only
4. cholera
Show answer
Answer: (d) cholera. Water-borne.
Why do vaccines protect us?
1. they kill all germs in the body
2. they train the immune system to recognise a germ
3. they replace food
4. they cure every disease
Show answer
Answer: (b) they train the immune system to recognise a germ. Memory cells respond fast later.
Which practice best prevents cholera?
1. covering the face
2. drinking boiled or clean water
3. using mosquito nets
4. exercising daily
Show answer
Answer: (b) drinking boiled or clean water. Cholera spreads through contaminated water.
Vaccines protect us by
1. killing all germs in the body
2. training the body to make antibodies in advance
3. replacing blood
4. acting as vitamins
Show answer
Answer: (b) training the body to make antibodies in advance. Immune memory.

All chapters of Class 8 Science

Written by Kundali IQ from standard, well-established facts to help with revision. This is not an official NCERT publication; always read your textbook too.