This MCQ module is based on: NCERT Exercises and Solutions: Human Health and Disease
TOPIC 34 OF 64
NCERT Exercises and Solutions: Human Health and Disease
🎓 Class 12
Biology
CBSE
Theory
Ch 7 – Human Health and Disease
⏱ ~8 min
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NCERT Exercises and Solutions: Human Health and Disease
Chapter Summary — Human Health and Disease
Common Diseases
Bacterial: typhoid (Salmonella typhi, Widal test), pneumonia (Streptococcus/Haemophilus). Viral: common cold (Rhinovirus). Protozoan: malaria (Plasmodium, female Anopheles vector, two hosts), amoebiasis (Entamoeba histolytica, houseflies). Helminths: ascariasis, filariasis (Wuchereria). Fungal: ringworm.
Immunity
Innate (non-specific, 4 barriers from birth) vs Acquired (specific, with memory). Acquired: humoral (B-cells, antibodies) + cell-mediated (T-cells). Antibody = H₂L₂ Y-shape with 2 binding sites. IgA, IgM, IgG, IgE, IgD.
Vaccination & Allergy
Active immunity: vaccine → body makes antibodies. Passive: ready-made antibodies (colostrum, antivenom). Allergy = exaggerated IgE-mediated response; histamine release. Autoimmune (rheumatoid arthritis).
Lymphoid Organs
Primary: bone marrow, thymus. Secondary: spleen, lymph nodes, tonsils, Peyer's patches, appendix. MALT = 50% of body's lymphoid tissue.
AIDS
HIV = retrovirus (RNA + reverse transcriptase). Targets helper T-cells via CD4 receptor. Transmits via sex, blood, needles, mother→child. Diagnosis: ELISA. Treatment: ARV drugs (partial). Prevention: NACO awareness, safe blood, condoms, disposable needles.
Cancer
Loss of contact inhibition → tumour. Benign (local) vs malignant (metastatic). Types: carcinoma, sarcoma, leukemia, lymphoma. Causes: carcinogens (radiation, chemicals, oncogenic viruses, c-onc). Detection: biopsy, CT, MRI. Treatment: surgery + radiotherapy + chemotherapy + immunotherapy (α-interferon).
Drug/Alcohol Abuse
Opioids (morphine, heroin — Papaver somniferum). Cannabinoids (Cannabis sativa). Cocaine (Erythroxylum coca). Tobacco (nicotine — cancer, CHD). Addiction (psychological) and dependence (physiological withdrawal). Adolescents most vulnerable. Prevention via peer support, counselling, rehab.
Common Abbreviations
| Abbreviation | Full form |
|---|---|
| MALT | Mucosa-Associated Lymphoid Tissue |
| CMI | Cell-Mediated Immunity |
| AIDS | Acquired Immuno Deficiency Syndrome |
| HIV | Human Immunodeficiency Virus |
| NACO | National AIDS Control Organisation |
| ELISA | Enzyme-Linked Immuno-Sorbent Assay |
| WHO | World Health Organization |
| Ig | Immunoglobulin (antibody) |
| TH | Helper T-lymphocyte |
| CT | Computed Tomography |
| MRI | Magnetic Resonance Imaging |
| RT | Reverse Transcriptase |
NCERT Exercises — Full Solutions
Q1. What are the various public health measures, which you would suggest as safeguard against infectious diseases?
Personal hygiene measures:
Vaccination: Childhood immunisation against polio, diphtheria, pneumonia, tetanus, measles, hepatitis B etc.
- Keep body clean; wash hands with soap before meals and after using the toilet.
- Consume clean drinking water; boil or filter if not sure.
- Wash fruits and vegetables before eating; cook food properly.
- Proper disposal of waste and excreta.
- Periodic cleaning and disinfection of water reservoirs, pools, tanks.
- Hygienic practices in public catering, restaurants, food stalls.
- Sewage management to prevent water contamination.
- Eliminate stagnant water; clean coolers regularly.
- Use mosquito nets; install wire mesh on doors and windows.
- Introduce larvivorous fish (e.g., Gambusia) into ponds.
- Spray insecticides in ditches, drainage and swamps.
Vaccination: Childhood immunisation against polio, diphtheria, pneumonia, tetanus, measles, hepatitis B etc.
Q2. In which way has the study of biology helped us to control infectious diseases?
Biology has provided several tools to control infectious diseases:
- Identification of pathogens — Microscopy, biochemical tests, molecular methods identify the exact agent.
- Understanding life cycles — e.g., the Plasmodium life cycle identifies the mosquito vector — enabling targeted vector control.
- Vaccination — Modern vaccines (some made by recombinant DNA, like hepatitis B from yeast) protect millions. Smallpox eradicated.
- Antibiotics — Discovery of penicillin and subsequent antibiotics has transformed the treatment of bacterial diseases.
- Diagnostic tests — ELISA (for HIV), Widal test (typhoid), PCR (many infections) enable early diagnosis.
- Public health epidemiology — Understanding how diseases spread guides prevention policies.
- Genomics — Genome sequencing of pathogens identifies new vaccines and drug targets.
Q3. How does the transmission of each of the following diseases take place? (a) Amoebiasis (b) Malaria (c) Ascariasis (d) Pneumonia
| Disease | Pathogen | Mode of Transmission |
|---|---|---|
| (a) Amoebiasis | Entamoeba histolytica | Contaminated food & water (faecal–oral). Houseflies act as mechanical carriers from infected faeces to food. |
| (b) Malaria | Plasmodium spp. | Bite of female Anopheles mosquito (biological vector). Two hosts: human (intermediate) + mosquito (definitive). |
| (c) Ascariasis | Ascaris lumbricoides | Eggs in faeces contaminate soil, water, vegetables, fruits. Healthy person ingests them through contaminated food/water. |
| (d) Pneumonia | Streptococcus pneumoniae, Haemophilus influenzae | Inhalation of droplets/aerosols from infected person; sharing glasses and utensils. |
Q4. What measures would you take to prevent water-borne diseases?
Water-borne diseases (typhoid, amoebiasis, cholera, ascariasis, hepatitis A/E) are caused by drinking or contact with contaminated water.
Prevention measures:
Prevention measures:
- Boil drinking water for at least 10 minutes — kills most pathogens. Alternatives: filtration, chlorination, UV treatment.
- Protect water sources — cover wells, tanks; prevent sewage seepage.
- Hygienic sanitation — separate sewage from drinking water; do not defecate near water sources.
- Wash hands with soap before food and after toilet.
- Wash fruits and vegetables thoroughly before eating raw.
- Avoid street food from places using unfiltered water.
- Disinfect water reservoirs periodically with chlorine.
- Vaccination where available (typhoid, hepatitis A).
- Community awareness — especially in monsoon when waterborne disease outbreaks are common.
Q5. Discuss with your teacher what does 'a suitable gene' means, in the context of DNA vaccines.
DNA vaccines contain a piece of pathogen DNA inserted into a small circular plasmid. When injected, the recipient's own cells take up the plasmid, express the encoded antigen, and trigger an immune response.
A 'suitable gene' for a DNA vaccine should:
A 'suitable gene' for a DNA vaccine should:
- Encode a strong antigen from the pathogen — usually a surface protein (e.g., HIV gp120, SARS-CoV-2 spike protein) that the immune system can recognise and target.
- Be highly conserved — i.e., not subject to rapid mutation, so the vaccine remains effective.
- Be safe — must not encode any toxin or disease-causing function on its own; should not integrate into the host genome.
- Be easily expressible in human cells — appropriate promoters, codon usage.
- Induce broad and long-lasting immunity — ideally both antibody (humoral) and T-cell (cellular) responses.
Q6. Name the primary and secondary lymphoid organs.
Primary lymphoid organs (where immature lymphocytes mature into antigen-sensitive lymphocytes):
- Bone marrow — source of all blood cells; site of B-cell maturation.
- Thymus — site of T-cell maturation; large at birth, shrinks after puberty.
- Spleen — filters blood-borne microbes.
- Lymph nodes — distributed along lymphatic vessels.
- Tonsils — guard the throat.
- Peyer's patches — in the small intestine.
- Appendix — at the start of the large intestine.
- MALT (Mucosa-Associated Lymphoid Tissue) — in the lining of respiratory, digestive, urogenital tracts (~50% of body's lymphoid tissue).
Q7. Expand the following abbreviations: (a) MALT (b) CMI (c) AIDS (d) NACO (e) HIV
(a) MALT = Mucosa-Associated Lymphoid Tissue
(b) CMI = Cell-Mediated Immunity
(c) AIDS = Acquired Immuno Deficiency Syndrome
(d) NACO = National AIDS Control Organisation
(e) HIV = Human Immunodeficiency Virus
(b) CMI = Cell-Mediated Immunity
(c) AIDS = Acquired Immuno Deficiency Syndrome
(d) NACO = National AIDS Control Organisation
(e) HIV = Human Immunodeficiency Virus
Q8. Differentiate the following and give examples of each: (a) Innate and acquired immunity (b) Active and passive immunity
(a) Innate vs Acquired Immunity
(b) Active vs Passive Immunity
| Feature | Innate | Acquired |
|---|---|---|
| Presence | From birth | After exposure |
| Specificity | Non-specific | Pathogen-specific |
| Memory | None | Yes |
| Mediators | Skin, mucus, stomach acid, phagocytes, interferons | B-cells, T-cells, antibodies |
| Speed | Immediate | 1–2 weeks (primary); rapid (secondary) |
| Example | Skin barrier; tear lysozyme | Immunity after chickenpox |
| Feature | Active | Passive |
|---|---|---|
| Source of antibodies | Person's own immune system | External source (mother / animal serum) |
| Onset | Slow (1–2 weeks) | Immediate |
| Duration | Long (years/life) | Short (weeks to months) |
| Memory | Yes | No |
| Example | Vaccination; recovery from measles | Colostrum to newborn; tetanus antitoxin; snake antivenom |
Q9. Draw a well-labelled diagram of an antibody molecule.
- 2 Heavy (H) chains — long polypeptides forming the stem.
- 2 Light (L) chains — short polypeptides on outer side of arms.
- Disulphide bonds (S–S) — link H–L and H–H chains.
- Antigen-binding sites — 2 per molecule, at the tips of the arms.
- Variable (V) region — at antigen-binding tips.
- Constant (C) region (Fc) — the stem.
- Hinge region — flexible joint.
- Overall Y-shape and notation H₂L₂.
Q10. What are the various routes by which transmission of human immunodeficiency virus takes place?
HIV is transmitted through body fluids by the following routes:
- Sexual contact with an infected person (most common route worldwide).
- Transfusion of contaminated blood or blood products.
- Sharing infected needles and syringes — common among intravenous drug users.
- Mother to child — through the placenta during pregnancy, during childbirth, or through breast milk.
Q11. What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?
Step-by-step mechanism:
- HIV enters the body and infects macrophages via the CD4 receptor on their surface.
- Inside the macrophage, reverse transcriptase copies the viral RNA into DNA.
- The viral DNA integrates into the host cell's chromosome — becoming a permanent provirus.
- The host cell now produces new HIV particles continuously, acting as an "HIV factory."
- HIV particles released into the blood also infect helper T-lymphocytes (TH), which also carry the CD4 receptor.
- Replication inside TH cells produces more virions; the infected TH cells die.
- Cycle repeats — the number of helper T-cells progressively decreases.
- Helper T-cells are the central coordinators of the immune system — they activate B-cells, cytotoxic T-cells and macrophages. Without them, the adaptive immune system collapses.
- The patient becomes immuno-deficient — unable to fight opportunistic infections (Mycobacterium, fungi, Toxoplasma) that would not affect a healthy person.
- Death usually occurs from these opportunistic infections, not from HIV directly.
Q12. How is a cancerous cell different from a normal cell?
| Feature | Normal cell | Cancer cell |
|---|---|---|
| Cell division | Highly controlled; stops on signal | Uncontrolled, continuous |
| Contact inhibition | Present — cells stop dividing on contact | Absent — cells pile up |
| Differentiation | Specialised for tissue function | De-differentiated, primitive |
| Nucleus | Normal size and shape | Large, abnormal shape |
| Lifespan | Limited (programmed apoptosis) | Immortal — escape apoptosis |
| Mobility | Stay in tissue of origin | Invade neighbours; metastasise |
| Resource use | Cooperative with neighbours | Compete and starve normal cells |
| Form | Organised into proper tissue architecture | Disorganised mass (tumour) |
Q13. Explain what is meant by metastasis.
Metastasis is the property of malignant tumours by which cancer cells break off from the primary tumour, travel through the blood or lymphatic system, lodge in distant organs, and form secondary tumours at those new sites.
Why it is feared: Most cancer deaths are caused by metastases, not by the original tumour. Secondary tumours often grow in vital organs (lung, liver, brain, bone), disrupting their function. Surgical removal becomes impossible once cancer has spread to multiple sites.
Example: Breast cancer commonly metastasises to bone, liver and brain. Once metastasised, the cancer is classified as "stage IV" and is much harder to treat than localised early-stage cancer.
Why early detection matters: Cancer treatment is far more effective when the tumour is still localised (no metastasis). This is the rationale for screening tests like mammograms and Pap smears.
Why it is feared: Most cancer deaths are caused by metastases, not by the original tumour. Secondary tumours often grow in vital organs (lung, liver, brain, bone), disrupting their function. Surgical removal becomes impossible once cancer has spread to multiple sites.
Example: Breast cancer commonly metastasises to bone, liver and brain. Once metastasised, the cancer is classified as "stage IV" and is much harder to treat than localised early-stage cancer.
Why early detection matters: Cancer treatment is far more effective when the tumour is still localised (no metastasis). This is the rationale for screening tests like mammograms and Pap smears.
Q14. List the harmful effects caused by alcohol/drug abuse.
Immediate effects:
- Reckless behaviour, vandalism, violence.
- Coma and death due to respiratory failure, heart failure or cerebral hemorrhage (with overdose).
- Especially dangerous: combining drugs OR drug + alcohol (overdose risk).
- Liver cirrhosis (alcohol).
- Damage to the nervous system.
- Tobacco — cancer of lung, throat, urinary bladder, oral cavity; bronchitis; emphysema; coronary heart disease; gastric ulcer.
- Intravenous drug use → AIDS and Hepatitis B from shared needles.
- Foetus is adversely affected — foetal alcohol syndrome; developmental defects.
- Academic and career decline; school/college absence.
- Withdrawal, isolation, depression, mood changes.
- Damaged family and peer relationships; financial ruin.
- Crime (stealing to fund habit).
- Masculinisation in females; testicular shrinkage in males.
- Acne, mood swings, aggressiveness, depression.
- Liver and kidney damage.
- Stunted growth in adolescents (premature long-bone growth-plate closure).
Q15. Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
Yes — peer pressure is one of the most powerful motivators for adolescents to try drugs and alcohol, especially in early adolescence when peer acceptance feels intensely important.
Self-protection strategies:
Self-protection strategies:
- Choose your friends wisely — Spend time with people who share your values and goals; avoid groups that pressure you to break rules.
- Learn to refuse confidently — Practice saying "no" politely but firmly: "Not for me, thanks." Do not argue or justify.
- Have a ready excuse — "I have to drive home," "My parents will smell it," "I'm in training for sports."
- Walk away — Leave situations where you feel pressured; you do not owe anyone an explanation.
- Develop healthy alternatives — Sports, music, art, debate, volunteering — keep your time meaningful so you are not idle and bored.
- Talk to a trusted adult — Parents, teachers, school counsellors. Asking for help is a sign of strength, not weakness.
- Remember: "cool" is temporary, addiction is forever — many adults regret choices made under teenage peer pressure.
- Be a positive influence — Your "no" gives others permission to say "no" too. Real friends respect your choices.
Q16. 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.
Three interlocking mechanisms make quitting difficult:
- Tolerance: With repeated use, the brain's receptors become less responsive to the drug. Larger doses are needed to produce the same pleasurable effect → escalating intake.
- Addiction (psychological): The brain's reward system associates the drug with intense pleasure and stress relief. Powerful cravings drive the person to seek the drug even when they know it is harming them. The drug "hijacks" the natural reward circuitry meant to motivate eating, social bonding and survival.
- Dependence (physiological): The body adapts to the drug being constantly present. If the drug is stopped, the body produces a withdrawal syndrome — anxiety, shakiness, nausea, sweating, depression, intense cravings. Symptoms can be severe and even life-threatening (e.g., delirium tremens in alcohol withdrawal).
- Social environment — friends still using; family conflict; financial stress.
- Mental health — many users have underlying depression or anxiety that the drug temporarily masks.
- Memory cues — places, people, smells associated with past use trigger cravings even years after quitting.
Q17. In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided?
Motivators (causes):
- Curiosity and need for adventure — typical of adolescent psychology.
- Peer pressure — desire to fit in or look "cool."
- Academic and competitive stress — drugs/alcohol seem to offer temporary relief.
- Family problems — instability, neglect, abuse, parental conflict.
- Media influence — TV, films, social media glamourising drug/alcohol use.
- Easy availability — drugs accessible at parties, schools, neighbourhoods.
- Mental health issues — depression, anxiety driving self-medication.
- Boredom and lack of meaningful activity.
- Avoid undue peer pressure — respect each child's individual personality; do not push them to perform beyond their limits.
- Education and counselling — teach life skills, problem-solving, stress management; channel energy into sports, music, art, yoga, hobbies.
- Seek help from parents and peers — encourage open communication; build trust at home so children share problems.
- Look for danger signs — parents and teachers should be alert to drops in performance, isolation, mood changes; intervene early.
- Professional and medical help — counsellors, psychiatrists, de-addiction and rehab programmes are available; affected individuals with sufficient will can recover fully.
- Strict regulation — enforce age limits on alcohol/tobacco sales; control advertising; school-based drug awareness programmes.
- Role models — parents, teachers and celebrities who model healthy behaviour have outsize influence.
Interactive: Health Concept Quick-Reference
Pick a topic to see its key takeaway:
Key takeaway: —
Activity 8.5 — Apply: A Family Wellness Audit
Setup: Apply what you have learned in this chapter to your own family — without naming anyone publicly.
Predict and reflect:
- List 3 personal hygiene habits your family follows well.
- List 2 improvements you could make in your home's public hygiene (water storage, waste disposal, mosquito control).
- Check your family's vaccination records — are all childhood vaccines complete?
- Discuss with a parent: How does the family handle stress? Are healthy outlets (sports, hobbies) available?
Suggested talking points:
- Hand-washing before meals, separating raw and cooked foods, and boiling drinking water during monsoon are simple and high-impact.
- Empty water containers weekly; use mosquito nets; install mesh on windows.
- Check the Universal Immunisation Programme schedule — BCG, OPV, MMR, DPT, hepatitis B etc.
- Family meals, screen-free time, regular physical activity, and open conversations build resilience against stress and substance abuse.
- If you spot warning signs (academic decline, mood changes, isolation in any family member), recommend professional help — not punishment.
Why this matters: Health is built one habit at a time, in one home at a time. Public health begins at the personal level.
Competency-Based Questions
Q1. The largest secondary lymphoid organ in the human body is: L1 Remember
Answer: (b) Spleen. Bean-shaped, on the left side of the abdomen — filters blood-borne microbes, stores RBCs, contains lymphocytes and phagocytes. Thymus and bone marrow are PRIMARY lymphoid organs.
Q2. Which is NOT a function of helper T-cells (TH)? L2 Understand
Answer: (c) Directly produce antibodies. TH cells coordinate the immune response but do NOT make antibodies themselves — that is the job of B-cells (which differentiate into plasma cells). HIV's destruction of TH cells explains AIDS' devastating impact on the whole immune system.
Q3. Short Answer: Why does an infant get immunity through colostrum but not through cow's milk? L3 Apply
Answer: Colostrum (the first breast milk in mammals) is rich in IgA antibodies specific to pathogens the mother has encountered. These antibodies coat the infant's gut and protect against gut infections during the first weeks — natural passive immunity.
Cow's milk contains COW antibodies — not effective against most human pathogens. Furthermore, cow's milk has different protein composition (more casein, less whey, different amino acid balance) that is less suitable for human infant digestion.
WHO recommends exclusive breastfeeding for at least the first 6 months. Mother's milk also contains live immune cells, growth factors and the optimal nutrient mix for human brain and gut development.
Cow's milk contains COW antibodies — not effective against most human pathogens. Furthermore, cow's milk has different protein composition (more casein, less whey, different amino acid balance) that is less suitable for human infant digestion.
WHO recommends exclusive breastfeeding for at least the first 6 months. Mother's milk also contains live immune cells, growth factors and the optimal nutrient mix for human brain and gut development.
Q4. Analyse: Compare the modes of action of anti-retroviral drugs and antibiotics. Why do antibiotics not work against AIDS? L4 Analyse
Antibiotics target unique features of bacterial cells:
Anti-retroviral (ARV) drugs target HIV-specific molecules:
- Cell wall (penicillins block synthesis)
- Ribosomes (different from human ribosomes — tetracycline targets 30S subunit)
- Bacterial DNA replication (quinolones)
- Folate synthesis (sulphonamides)
Anti-retroviral (ARV) drugs target HIV-specific molecules:
- Reverse transcriptase (e.g., AZT, tenofovir)
- HIV protease (e.g., ritonavir)
- Integrase (e.g., raltegravir)
- Entry/fusion (e.g., enfuvirtide)
Q5. HOT (Create): Design a 1-week meal-plan for a teenager that supports healthy immunity and reduces cancer risk. Justify your choices. L6 Create
Sample Day 1 Plan (vegetarian Indian, 2,200 kcal):
- Breakfast: Oats + banana + nuts; one boiled egg or paneer; one orange.
- Mid-morning: Curd with seeds (probiotic; protein).
- Lunch: Brown rice + dal + sabzi (green leafy or cruciferous like cauliflower/cabbage) + salad + buttermilk.
- Evening: Roasted chana + tea; or one fruit.
- Dinner: Roti + paneer/dal + cooked vegetables + curd.
- Hydration: 2.5–3 L water; minimal sugary drinks.
- Antioxidants (Vit C, E, β-carotene) — found in citrus, berries, carrots, leafy greens — neutralise free radicals that cause DNA damage and cancer.
- Cruciferous vegetables (broccoli, cabbage, cauliflower) — contain sulphoraphane, linked to reduced cancer risk.
- Probiotics (curd, fermented foods) — support gut microbiome and innate immunity.
- Whole grains and pulses — provide fibre and slow-release carbs; lower risk of colorectal cancer.
- Lean protein (eggs, paneer, dal, fish) — supports antibody production.
- Limit: red and processed meats (WHO Group 1 carcinogen); deep-fried foods; sugary drinks; alcohol (esp. teen years).
- Add: 30–45 min daily physical activity; 7–9 hours sleep; sunlight for vitamin D.
Assertion–Reason Questions
Choose: (A) Both true, R explains A. (B) Both true, R doesn't explain A. (C) A true, R false. (D) A false, R true.
A: Vaccination produces immunological memory.
R: Memory B and T cells generated by vaccination respond rapidly to the actual pathogen on later exposure.
Answer: (A). Both true; R explains A. The memory mechanism is what makes vaccines effective — without it, every infection would be a new challenge to the immune system.
A: A patient who recovers from chickenpox usually does not get it again.
R: Recovery from the disease produces active natural immunity with long-lasting memory cells.
Answer: (A). Both true; R explains A. This is the "natural" parallel to vaccination — the body's memory of the first encounter prevents serious disease on second exposure.
A: Sharing of injection needles can transmit AIDS.
R: HIV particles can survive for hours in the residual blood of an infected needle and may enter a new user's bloodstream.
Answer: (A). Both true; R explains A. This is why disposable needles and "needle exchange" programmes are central to HIV prevention among intravenous drug users.
Frequently Asked Questions - NCERT Exercises and Solutions: Human Health and Disease
What are the most-asked NCERT exercise questions in Chapter Human Health and Disease?
NCERT Class 12 Biology Chapter on Human Health and Disease exercises cover definitions, mechanisms, labelled diagrams, comparison tables, and application-based questions. The MyAiSchool solution set provides full step-by-step solutions for every NCERT question, aligned with the CBSE board exam pattern. Students should master scientific terminology, mechanism flowcharts, and concept comparison to score full marks.
How should students approach diagram-based questions in Human Health and Disease?
For diagram-based questions in NCERT Class 12 Biology Chapter on Human Health and Disease: (1) draw clean, proportional, large diagrams with sharp pencil lines, (2) label all parts horizontally on the right side using a ruler, (3) use scientific terminology (Latin/Greek names where applicable), (4) write a 1-2 line description if asked. The MyAiSchool solutions provide editable reference diagrams aligned with NCERT textbook figures.
What types of CBSE board questions come from Human Health and Disease?
CBSE Class 12 Biology board questions from Human Health and Disease typically include: (1) 1-mark MCQs on definitions and processes, (2) 2-mark short-answer mechanism/comparison questions, (3) 3-mark labelled-diagram questions, (4) 5-mark long-answer essays combining mechanism + diagram + significance. The MyAiSchool exercise set tags each question by mark weight and Bloom level (L1-L6).
How do I compare two biological processes in 5-mark questions?
For 5-mark comparison questions in NCERT Class 12 Biology on Human Health and Disease: (1) use a two-column table with feature headings down the left side, (2) compare on at least 5-6 features (definition, location, mechanism, control, outcome, significance), (3) include one labelled diagram if relevant, (4) end with biological significance. The MyAiSchool solutions follow this CBSE-aligned tabular format consistently for full marks.
What are common mistakes in Human Health and Disease exercises?
Common mistakes in NCERT Class 12 Biology Human Health and Disease include: (1) confusing similar terms (mitosis vs meiosis, syngamy vs triple fusion, etc.), (2) skipping intermediate steps in mechanisms, (3) missing examples or species names, (4) writing essays when tables are expected, (5) forgetting biological significance. The MyAiSchool solutions highlight these traps with red flags so students avoid losing marks.
How does the MyAiSchool solution differ from other NCERT solution sets?
MyAiSchool Class 12 Biology Human Health and Disease solutions use NEP 2024-aligned pedagogy with Bloom Taxonomy tagged questions (L1 Remember to L6 Create), step-by-step working with biological reasoning, fully labelled SVG diagrams, comparison tables, interactive simulations, and Competency-Based Questions (CBQs) for board exam practice. Each solution is verified against NCERT and CBSE marking schemes.
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