AP 8th Biology Textbook Solutions – 2. Health (2026-27)

2 Health

Probe and Ponder (Page 254)

• How does your body respond to an infection such as common cold?
  Our body's immune system responds by fighting the pathogens, which may result in symptoms like nasal congestion, sore throat, fever, and coughing.
• We rarely see cases of smallpox or polio these days, but diseases like diabetes and heart problems are more common. Why?
  Smallpox and polio are communicable diseases that have been controlled or eradicated through vaccination. Diseases like diabetes and heart problems are non-communicable lifestyle diseases becoming more common due to changes like eating processed food, less exercise, and longer lifespans.
• Could climate change lead to new types of diseases?
  Yes, climate change and environmental factors can alter the habitats of disease-carrying vectors (like mosquitoes) and pathogens, potentially spreading new types of diseases to new areas.
• How do emotions like stress or worry affect us and make us sick?
  Health is a state of physical, mental, and social well-being. Stress, worry, and loneliness can negatively affect our mental health, leading to physical symptoms like headaches, poor sleep, and a weakened immune system.
• Why do some groups of people get affected more than others during disease outbreaks?
  Some groups may have a weaker immune system, lack access to clean environments and balanced diets, or live in unhygienic conditions, making them more susceptible to pathogens.

Activity 2.1: Let us observe (Page 256)

• Think and Reflect: What was the cause of the boy's health problems?
  The boy's health problems were caused by feeling lonely in a new environment and spending excessive time on his phone and social media to cope with his lack of friends.
• How did his habits and surroundings affect his well-being?
  His lack of social interaction and high screen time negatively impacted his mental and physical well-being, leading to headaches, weight loss, and poor sleep.

Activity 2.2: Let us list (Page 258)

• Which ones would you like to start following? Add to the list below:
  • Drink adequate amounts of clean water daily.
  • Maintain proper posture while studying and sitting.
  • Wash hands with soap before eating and after using the toilet.
• Now, think about habits that are not good for your health. Add more to the list below:
  • Eating food without washing hands.
  • Living an inactive lifestyle without physical exercise.
  • Drinking too many sugary beverages or consuming tobacco.

Activity 2.3: Let us compare (Page 260)

• Look at Fig. 2.3a and Fig. 2.3b. Which playground would you like to play in, and why?
  I would like to play in the playground shown in Fig. 2.3a because it is clean, well-maintained, and beautiful, whereas Fig. 2.3b is polluted, unhygienic, and full of disease-causing vectors like flies and mosquitoes.
• Have you ever found it hard to breathe in a place with a lot of smoke or dust?
  Yes, places with smoke and dust have high air pollution, which makes it hard to breathe and can cause problems like coughing or asthma.

In-text Questions (Page 268)

• Are diseases always caused by infections?
  No, not all diseases are caused by infections. Non-communicable diseases, such as cancer, diabetes, asthma, and nutritional deficiencies, are linked to lifestyle, diet, or environmental factors rather than pathogens.
• Are any diseases eradicated or eliminated?
  Yes, certain diseases like smallpox have been completely eradicated worldwide through mass vaccination programs.

In-text Questions (Page 270)

• What will happen if I take excess mount of Iodine?
  Consuming an excess amount of iodine can disrupt the normal functioning of the thyroid gland, potentially leading to thyroid-related health problems.

Activity 2.5: Let us survey (Page 270)

• Fill in Table 2.2 and learn more about lifestyle-related diseases.

  S.No	Name of common lifestyle-related diseases	Signs and symptoms	Suggested lifestyle change(s)
  1.	Obesity	Excessive body weight, fatigue, breathlessness	Eating a balanced diet and exercising regularly
  2.	Diabetes	Frequent urination Excessive thirst Weight loss Tiredness Slow healing of wounds	Reducing processed and sugary foods, staying physically active
  3.	High blood pressure	Headache, dizziness, shortness of breath	Reducing salt intake, managing stress through yoga or meditation, regular exercise

Activity 2.6: Let us read (Page 272)

• What do you infer from this case study?
  I infer that adopting simple community-led sanitation practices, such as building and using toilets, significantly reduces open defecation, which in turn drastically lowers the spread of communicable diseases like diarrhoea and infections in children.

In-text Questions (Page 274)

• Do you know when the first vaccine was discovered?
  The first vaccine was discovered in the late 1700s by an English doctor named Edward Jenner, who created a vaccine for smallpox using the milder cowpox virus.

Activity 2.7: Let us infer (Page 280)

• Study the infographic given in Fig. 2.5b. How do you think the antibiotic resistance has been developed in bacterial pathogens? What precautions may be taken to reduce antibiotic resistance?
  Antibiotic resistance develops when antibiotics are taken unnecessarily or given to farm animals. The antibiotics kill good and susceptible bacteria, allowing the few resistant bacteria to survive, multiply, and transfer their resistance to other bacteria.
  
  Precautions include using antibiotics only when prescribed by a doctor, taking the correct dose for the right duration, and avoiding unnecessary antibiotic injections for cattle.

Keep the curiosity alive (Page 284 - 286)

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

  Disease	Type
  Cold and flu	Communicable
  Typhoid	Communicable
  Diabetes	Non-communicable
  Asthma	Non-communicable
  Chicken pox	Communicable

• 2. 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
  A. (i) and (ii)

  B. (ii) and (iii)

  C. (i) and (iv)

  D. (ii) and (iv)
  Answer: B. (ii) and (iii)
• 3. 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?
  The school should advise sick students to stay home and rest, mandate wearing masks, promote frequent hand washing with soap, and ensure classrooms are well-ventilated and surfaces are sanitized.
  
  (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?
  I would politely ask them to cover their mouth and nose while coughing or sneezing and gently suggest they wear a mask or visit the school nurse for their well-being.
  
  (iii) How can you protect yourself and others from getting infected in this situation?
  I can protect myself by wearing a mask, frequently washing my hands, avoiding sharing personal items like handkerchiefs, and maintaining good personal hygiene.
• 4. 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?
  We should pack mosquito nets and repellents, wear long-sleeved clothes to prevent mosquito bites during the trip, and monitor for symptoms like high fever and chills after returning.
  
  (ii) How can you explain the importance of mosquito nets or repellents to your sibling?
  I would explain that malaria is a communicable disease spread by infected mosquitoes (vectors), and using nets and repellents blocks these insects from biting us and transmitting the disease.
  
  (iii) What could happen if travellers ignore health advisories in such areas?
  If travellers ignore health advisories, they have a high risk of being bitten by infected mosquitoes and contracting malaria, which causes severe illness.
• 5. 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?
  I would respectfully tell him that we care about his long-term health and remind him that avoiding harmful substances like tobacco is crucial to prevent serious non-communicable diseases like cancer and asthma.
  
  (ii) What would you do if your friend offers you a cigarette at a party?
  I would firmly say "NO" because healthy habits are important for physical well-being, and consuming addictive substances is dangerous.
  
  (iii) How can schools help prevent students from indulging in such harmful habits?
  Schools can organize awareness campaigns, involve students in health and fitness programs, and provide counseling to teach the importance of a healthy lifestyle and the dangers of addiction.
• 6. 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?
  Vinita could ask: "Do antibiotics work against viral infections like the common cold or dengue?" or "What happens if bacteria develop antibiotic resistance because we use antibiotics too often?".
• 7. Imagine you are in charge of a school health campaign. What key messages would you use to reduce communicable and non-communicable diseases?
  Key messages: Practice good personal hygiene and wash hands regularly to stop germs. Eat a balanced diet, exercise daily, and avoid junk food to prevent lifestyle diseases. Keep your surroundings clean to prevent mosquito breeding.
• 8. 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?
  Antibiotics are medicines designed specifically to kill bacteria by targeting parts of bacterial cells. They do not work against viruses; therefore, taking them for viral infections is ineffective and contributes to antibiotic resistance.
• 9. 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.
  Hepatitis A, Cholera, and Poliomyelitis.
• 10. The following table contains information about the number of dengue cases reported in a hospital over a period of one year. Critically analyse your findings and answer the following:
  (i) In which three months were the dengue cases highest?
  July, August, and September (65 cases each).
  
  (ii) In which month(s) were the cases lowest?
  January (10 cases).
  
  (iii) What natural or environmental factors during the peak months might contribute to the increase in dengue cases?
  The peak months correspond to the monsoon/rainy season, which creates stagnant water pools. Still water serves as a breeding ground for dengue-carrying mosquitoes.
  
  (iv) Suggest a few preventive steps that the community or government can take before the peak season to reduce the spread of dengue.
  Preventive steps include clearing areas with still water to control mosquito breeding, spreading awareness about using mosquito nets and repellents, and initiating community cleaning drives.
• 11. 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?
  This happens because of acquired immunity. During the first exposure, the immune system learns to recognize the pathogen. It remembers the germ, so upon a second exposure, it quickly recognizes and attacks the harmful pathogen much more effectively.