Health: The Ultimate Treasure NCERT Solutions | Science Curiosity Class 8 - New NCERT PDF Download

Probe and Ponder (Page: 28)

Q1. How does your body respond to an infection such as common cold? 

Ans: When you get an infection like the common cold, your body’s immune system fights back. You may get a runny nose, cough, fever, or feel tired—these are signs that your body is:

• Trying to get rid of the germs (by sneezing, coughing, or producing mucus)
• Raising your body temperature (fever) to make it harder for the germs to survive
• Making you rest so your body can recover

Q2. We rarely see cases of smallpox or polio these days, but diseases like diabetes and heart problems are more common. Why? 
​Ans:

• Smallpox and polio have become rare because of widespread vaccination, which protects people and stops these diseases from spreading.
• Diseases like diabetes and heart problems are now more common because of modern lifestyle changes: people eat more processed/junk food, exercise less, and live longer lives. These are called non-communicable diseases and are often linked to habits rather than infections.

Q3. Could climate change lead to new types of diseases? 

Ans: Yes. Climate change can cause new types of diseases or make old ones more common. For example:

• Warmer temperatures can help disease-carrying insects like mosquitoes (that spread dengue or malaria) survive in new places.
• Changing weather can create more floods or droughts, which can contaminate water and lead to more infections.
• Plants, animals, and microbes may behave differently, introducing new health risks to people.

Q4. How do emotions like stress or worry affect us and make us sick? 
​Ans: Emotions such as stress, worry, or sadness affect not just your mind but your body too:

• Long-term stress weakens the immune system, making it easier for you to fall sick.
• It can cause headaches, stomach problems, trouble sleeping, or lead to unhealthy habits (like bad eating or skipping exercise).
• Staying positive and managing stress helps keep both your body and mind healthy.

Q5. Why do some groups of people get affected more than others during disease outbreaks?
Ans: Some people are more affected during disease outbreaks because of:

• Weaker immune systems (young children, elderly, or those already sick)
• Poor living conditions or hygiene, making it easier for germs to spread
• Lack of access to vaccines, medicines, or clean water
• Close contact with more people or limited knowledge about how to protect themselves

So, health depends on your body, your habits, and your environment!

Q6. Share your questions
1. What habits do you think are important for staying healthy every day?
Ans: The following habits are important for daily good health:

• Eating a balanced and nutritious diet (with fruits, vegetables, and whole grains)
• Maintaining personal hygiene (bathing, brushing teeth, washing hands regularly)
• Exercising or being active every day
• Getting enough sleep every night
• Drinking clean water
• Spending time with family and friends for a healthy mind
• Limiting screen time (phones, TV, computers)
• Staying positive and managing stress (through relaxation, hobbies, or talking to someone)
• Saying no to harmful substances like tobacco, alcohol, and drugs

2. How do your surroundings (like home, school, or playground) affect your health?
Ans: Your surroundings affect health in many ways:

• Clean surroundings (at home, school, or playground) reduce germs, insects, and the chances of getting diseases.
• Dirty or polluted places can cause illnesses like cough, asthma, and infections.
• Playgrounds that are clean and safe encourage exercise and outdoor activities, which make you physically stronger.
• Clean water and good sanitation at home and school help prevent diseases spread by germs.
• People who live or study in healthy and hygienic environments feel happier, less stressed, and get sick less often.

Keep the curiosity alive (Page: 42)

Q1. Group the diseases shown in the images as communicable or non-communicable

Ans: 

​Communicable Diseases

• Cold and flu: Spread from person to person (through air, droplets, etc.).
• Typhoid: Spread through contaminated food and water.
• Chickenpox: Spread from person to person (through air or direct contact).

Non-Communicable Diseases

• Diabetes: Not caused by pathogens and does not spread from person to person; usually linked to lifestyle or genetic factors.
• Asthma: Not infectious; related to environmental, genetic, or lifestyle causes.

Q2. Diseases can be broadly grouped into communicable and non-communicable diseases. From the options given below, identify the non-communicable diseases. 
(i) Typhoid 
(ii) Asthma 
(iii) Diabetes 
(iv) Measles 
Options
(a) (i) and (ii) 
(b) (ii) and (iii) 
(c) (i) and (iv) 
(d) (ii) and (iv)

Ans: The non-communicable diseases from the options are Asthma and Diabetes.
So, the correct answer is:
(b) (ii) and (iii)

• Typhoid and Measles are communicable diseases (spread by germs from person to person).
• Asthma and Diabetes are non-communicable diseases (not spread from person to person; linked to genetics, lifestyle, or environment)

Q3. There is a flu outbreak in your school. Several classmates are absent, while some are still coming to school coughing and sneezing. 
(i) What immediate actions should the school take to prevent further spread? 
Ans: 

• Advise sick students to stay home until they are fully recovered.
• Inform parents and staff about the outbreak, its symptoms, and basic prevention steps.
• Encourage frequent hand washing and provide soap or hand sanitizers in classrooms and washrooms.
• Ensure classrooms are well-ventilated—open windows and doors if possible.
• Clean and disinfect frequently touched surfaces like desks, doorknobs, and washroom taps regularly.
• Remind everyone to cover their mouth and nose when coughing or sneezing (using a tissue, handkerchief, or elbow).
• Discourage sharing of personal items such as water bottles, food, and handkerchiefs.

(ii) If your classmate, who shares the bench with you, starts showing symptoms of the flu, how can you respond in a considerate way without being rude or hurtful? 
Ans: 

• Speak kindly and gently: You can say something like, "You don’t look well. Maybe you should tell the teacher or visit the school nurse."
• Offer them a tissue or hand sanitizer if they are coughing or sneezing.
• Encourage them to cover their mouth and nose while coughing or sneezing, if they aren’t already doing so.
• Keep a reasonable distance if possible, but without making them feel excluded or embarrassed.
• Do not tease or blame them—show understanding, as anyone can get sick.

(iii) How can you protect yourself and others from getting infected in this situation?
Ans: 

• Wash your hands often with soap and water, especially after touching shared surfaces or before eating.
• Avoid touching your face (nose, mouth, eyes) after touching surfaces in class.
• Use a mask if advised by the school—especially in crowded indoor spaces.
• Maintain a safe distance from those who are coughing or sneezing.
• Bring and use your own water bottle and stationery.
• Eat nutritious food and get enough sleep to keep your immune system strong.
• Tell your teacher if you start to feel unwell so that you can go home and recover, helping prevent spreading the illness.

Q4. By following these steps, you show care for yourself and everyone around you while strengthening good habits for health and kindness. Your family is planning to travel to another city where malaria is prevalent. 
(i) What precautions should you take before, during, and after the trip? 
Ans: Before the trip:

• Learn about malaria in the city you’re visiting.
• Visit a doctor for advice—sometimes preventive medicines (antimalarial tablets) may be recommended.
• Pack mosquito repellents, bed nets, and long-sleeved clothes.
• Make sure your vaccinations are up to date.

During the trip:

• Sleep under a mosquito net, especially at night.
• Apply mosquito repellent to skin and clothes, especially during dusk and dawn when mosquitoes are most active.
• Wear long-sleeved shirts, long pants, and socks to cover your skin.
• Stay in places with screened windows/doors or air conditioning if possible.
• Avoid areas with stagnant water, as these are mosquito breeding spots.

After the trip:

• Watch for symptoms like fever, shivering, body aches, or tiredness for several weeks after travel.
• Visit a doctor immediately if you feel unwell or develop a fever.
• Complete any recommended preventive medication even after returning.

(ii) How can you explain the importance of mosquito nets or repellents to your sibling? 
Ans: You can say:
"Malaria is spread by mosquito bites. Mosquito nets and repellents are like shields—they stop mosquitoes from biting us while we sleep or play. If we use them, we are much less likely to get sick. It’s a simple way to keep ourselves safe, just like wearing a helmet protects us when we ride a bike!"
(iii) What could happen if travellers ignore health advisories in such areas?
Ans: 

• They may get malaria, which can cause high fever, headaches, chills, and even serious complications that sometimes require hospitalization.
• Travellers could spread malaria to others when they come back home.
• Ignoring advisories can disrupt the trip with illness, miss school or work, and sometimes even lead to life-threatening situations.

Q5. Your uncle has started smoking just to fit in with his friends, even though it is well known that smoking can seriously harm health and even cause death. 
(i) What would you say to him to make him stop, without being rude? 
Ans: "Uncle, I care about you and want you to stay healthy. Smoking can cause really serious health problems, like lung cancer and heart disease. I read that it’s also really hard to stop once you start. Maybe you could try finding some healthier ways to relax and spend time with your friends? We all want you to live a long and happy life!"

Be respectful and show care for his well-being, instead of sounding judgmental or angry.

(ii) What would you do if your friend offers you a cigarette at a party? 
Ans: 

• I would politely say, "No, thanks. I don’t want to try smoking—it’s harmful for health, and I want to stay fit."
• If I feel uncomfortable, I can move away or change the topic.
• I can let my friend know that I prefer having fun in healthy ways—maybe suggest an alternative activity.

Remember: It's okay to say NO and you don’t need to do something just to fit in.

(iii) How can schools help prevent students from indulging in such harmful habits?
Ans: Schools can help by:

• Teaching students about the dangers of smoking, alcohol, and drugs during health and science classes.
• Organizing workshops or guest talks where doctors/ex-smokers share the real-life effects of harmful substances.
• Providing counseling and support for students who feel peer pressure or want to talk about their problems.
• Encouraging fun, healthy activities like sports, arts, and clubs so that students stay engaged and happy.
• Creating a strict "no smoking" policy on school premises and making sure everyone knows about it.

Q6. Saniya claims to her friend Vinita that “Antibiotics can cure any infection, so we don’t need to worry about diseases.” What question(s) can Vinita ask her to help Saniya understand that her statement is incorrect?

Ans: Here are some thoughtful questions Vinita can ask Saniya to help her understand why her statement about antibiotics is incorrect:

1. "Can antibiotics cure infections caused by viruses, like the common cold or flu?"
   (This helps highlight that antibiotics only work against bacteria, not viruses.)
2. "Do you know what could happen if people use antibiotics when they don’t need them?"
   (This can lead to a discussion about antibiotic resistance, where bacteria become stronger and can't be killed by the usual medicines.)
3. "Are there diseases that are not caused by bacteria, and if so, can antibiotics help with those?"
   (Some infections are caused by viruses, fungi, or protozoa, for which antibiotics don’t work.)
4. "If antibiotics could really cure any infection, why do doctors sometimes say you only need rest and fluids for certain illnesses?"
   (Doctors don’t prescribe antibiotics for viral infections because they won’t help.)

By asking these questions, Vinita can help Saniya understand that antibiotics are useful only for bacterial infections, not for all types of diseases or infections. Taking antibiotics unnecessarily can make future infections harder to treat.

Q7. The following table contains information about the number of dengue cases reported in a hospital over a period of one year:

Make a bar graph of the number of cases on the Y-axis and the month on the X-axis. Critically analyse your findings and answer the following: 
Ans: 

(i) In which three months were the dengue cases highest?
​The three months with the highest number of dengue cases are:

• July: 65 cases
• August: 65 cases
• September: 65 cases

These are the peak months where the number of cases remained the same and were the highest for the year.

(ii) In which month(s) were the cases lowest?

The lowest number of dengue cases was reported in January (10 cases). February (12 cases) and March (15 cases) are also low, but January is the lowest.

(iii) What natural or environmental factors during the peak months might contribute to the increase in dengue cases?

• Monsoon Season: July, August, and September usually coincide with the monsoon (rainy) season in India.
• Stagnant Water: Rain leads to water collecting in open containers, puddles, and drains where mosquitoes—especially the Aedes mosquito that carries dengue—breed rapidly.
• Warm and Humid Weather: This promotes faster mosquito reproduction and survival, increasing the risk of dengue spread.

(iv) Suggest a few preventive steps that the community or government can take before the peak season to reduce the spread of dengue

• Remove standing water from flower pots, coolers, tires, and containers to stop mosquito breeding.
• Fogging and spraying insecticides in neighborhood drains, garbage dumps, and stagnant water areas.
• Clean house gutters and water storage tanks regularly before and during the monsoon.
• Wear long sleeves and use mosquito repellents, especially during the rainy season.
• Awareness campaigns in schools and communities to educate about dengue prevention.
• Enforce municipal fines for collecting water in open containers to improve community participation in mosquito control.

By taking these steps before and during the monsoon, the community can help reduce the number of dengue cases significantly.

Q8. Imagine you are in charge of a school health campaign. What key messages would you use to reduce communicable and non-communicable diseases?
Ans: 
Key Health Messages:

Personal Hygiene

• Wash your hands often with soap, especially before eating and after using the toilet.
• Keep your body, clothes, and surroundings clean.

Healthy Eating

• Eat a balanced diet with plenty of fruits, vegetables, whole grains, and clean water.
• Avoid junk food and extremely sugary or fatty snacks.

Physical Activity

• Exercise or play outdoors every day to keep your body fit.

Vaccination

• Get vaccinated on time to prevent serious diseases like measles, polio, and hepatitis.

Prevent Disease Spread

• Cover your mouth and nose when coughing or sneezing.
• Stay home if you are sick to prevent spreading illness to others.
• Do not share personal items like water bottles or handkerchiefs.

Avoid Harmful Habits

• Say ‘NO’ to tobacco, alcohol, and addictive substances.

Good Sanitation

• Use toilets; do not practice open defecation.
• Keep water containers covered and drain any standing water to stop mosquitoes from breeding.

Mental and Social Well-being

• Talk to someone if you feel worried or stressed; maintaining friendships and a positive mind is important for health.

Q9. It is recommended that we should not take an antibiotic for a viral infection like a cold, a cough, or flu. Can you provide the possible reason for this recommendation?
Ans: Antibiotics only work against bacteria, not viruses. Diseases like the common cold, cough, or flu are caused by viruses, so antibiotics will not cure them. Taking antibiotics when they are not needed can also make bacteria in your body resistant, so they may not work when you truly need them for bacterial infections later.

Q.10. Which disease(s) among the following may spread if drinking water gets contaminated by the excreta from an infected person? Hepatitis A, Tuberculosis, Poliomyelitis, Cholera, Chickenpox
​Ans: The following diseases may spread if drinking water is contaminated by the excreta of an infected person:

• Hepatitis A
• Poliomyelitis (Polio)
• Cholera

Tuberculosis and Chickenpox do NOT spread via contaminated water from excreta; they mainly spread through the air from person-to-person contact.

Q11. When our body encounters a pathogen for the first time, the immune response is generally low but on exposure to the same pathogen again, the immune response by the body is much more compared to the first exposure. Why is it so?
Ans: 

• When our body faces a pathogen for the first time, the immune system’s response is usually weak because it is just learning to recognise and fight that germ. 
• After this first exposure, the immune system “remembers” the germ. If the same pathogen enters the body again, the immune system responds much faster and stronger because it is already prepared to fight it. 
• This is why vaccinations work—they help train our immune system so we are protected if we ever encounter the real germ in the future.

Discover, design, and debate (Page: 45)

1. Students maintain a health diary for at least a month to track food, hygiene, exercise, sleep, screen time, and emotional state.
Ans: 
​Purpose:To make students aware of their daily health habits and overall well-being.
How to Maintain a Health Diary (for at least a month):
Track the following every day:

• Food: What you ate (healthy/junk, balanced diet?)
• Hygiene: Whether you bathed, brushed teeth, washed hands before meals
• Exercise: Any physical activity (type and duration)
• Sleep: When you went to bed/woke up, total hours slept
• Screen Time: Hours spent watching TV, phone, computer
• Emotional State: How you felt (happy, stressed, sad, relaxed, etc.)

Sample Table (for one day):

Discussion: After a month, discuss:

• What healthy habits do you follow regularly?
• When do you feel your best, and why?
• Are there days when you felt tired or unhappy? Can you see any pattern related to sleep, food, or screen time?

2. Read about Indian scientists like Suniti Solomon, Asima Chatterjee, Dr. Yellapragada Subbarao, Dr. Mary Poonen Lukose for their contributions in the field of health and diseases
Ans: 

• Suniti Solomon:
  Leading Indian microbiologist who identified the first HIV cases in India and contributed greatly to AIDS awareness and treatment.
• Asima Chatterjee:
  Renowned chemist who developed anti-epileptic and anti-malarial drugs from Indian medicinal plants.
• Dr. Yellapragada Subbarao:
  Discovered important antibiotics (like tetracycline) and cancer-fighting drugs; work saved millions of lives worldwide.
• Dr. Mary Poonen Lukose:
  One of India’s first female doctors, led public health reforms and was instrumental in maternal and child health work in Kerala.

3. The deadly disease smallpox was eradicated by vaccination. Discover how this was done and why it worked. Debate whether everyone should be required to get vaccinated to protect others.
Ans: 
​How Smallpox Was Eradicated:

• A global vaccination campaign supplied smallpox vaccine worldwide.
• Public health workers vaccinated as many people as possible and quickly isolated new cases.

Why Did It Work?

• Smallpox spreads only between humans, so vaccinating people broke the infection chain.
• The vaccine gave strong, long-lasting immunity, and community-wide efforts meant there were no more places for the virus to spread.

Debate Statement:
“Should everyone be required to get vaccinated to protect others?”

Points For Mandatory Vaccination:

• Protects those who can’t get vaccinated (herd immunity)
• Prevents outbreaks and saves lives
• Eradication of diseases benefits everyone

Points Against Mandatory Vaccination:

• Personal choice and bodily autonomy
• Concerns about side effects (though vaccines are tested for safety)
• Some people may have genuine medical reasons to avoid vaccination

4. According to current guidelines, learn the correct sequence of steps for performing cardiopulmonary resuscitation (CPR) on an adult in case of sudden stoppage of breathing. School may invite a doctor or a professional to demonstrate a mock drill.

Ans: CPR (Cardiopulmonary Resuscitation) — Adult, latest steps (as per international guidelines):

1. Check responsiveness:
   Tap and shout to see if the person responds.
2. Call for help:
   Shout for assistance and ask someone to call emergency services (like 108 in India).
3. Open airway:
   Tilt the head back and lift the chin.
4. Check breathing:
   Look, listen, and feel for normal breathing for 10 seconds.
5. Chest compressions:
   Place heel of one hand on the center of the chest, other hand on top.
   Push hard and fast (at least 100–120 compressions per minute).
   Allow the chest to rise fully between compressions.
6. Rescue breaths (if trained and willing):
   Give 2 breaths after 30 compressions; pinch the nose, give a full breath by mouth.
   If not trained, do hands-only CPR (compressions only).

5. Invite a doctor to the school. Students may be encouraged to interact with the doctor on the issues of malnutrition, under-nutrition, and over-nutrition.
Ans: 

Prepare Questions Like:

• How can we identify malnutrition, under-nutrition, or over-nutrition?
• What are common signs and symptoms?
• Why is breakfast important?
• What foods should we eat more or less of?
• How do old and young people’s needs differ?
• Can we fall sick from eating too much processed food?

Post-visit Discussion:
Share key learnings, especially local issues related to food.

6. If you are given an opportunity to create a health card, what all would you like to include in it. Create your own health card and have discussion about it.
Ans: 

What to Include in a Health Card:

• Name, age, class, blood group
• Emergency contact details
• Vaccination record
• Height and weight (to track growth)
• Chronic diseases (if any, e.g., asthma, diabetes)
• Allergies (to food, medicines)
• Recent illnesses or injuries
• Physical/mental fitness notes
• Last medical/dental checkup date
• Remarks (doctor’s recommendations)

Activity:
Draw and fill your own health card. Discuss why each point is included and how it helps doctors or teachers care for you.

7. Have a debate on ‘Are there ill-effects of fast food on companion animals?

Ans: 
Debate Topic:
“Are there ill-effects of fast food on companion animals (pets)?”

Points For (Yes, there are ill-effects):

• Fast food is high in salt, sugar, and unhealthy fats, which can harm pets’ health.
• Leads to obesity, dental problems, and digestive issues in animals.
• Some ingredients (chocolate, onions, certain spices) are toxic to dogs and cats.

Points Against (No, if occasional and controlled):

• Small amounts, given rarely, may not cause immediate harm.
• Some pets may tolerate certain foods.

Conclusion:
Majority expert opinion: Fast food is unhealthy for animals; pets should get food designed for their species to stay fit and avoid illness.