Biology MCQs – 50 Solved Questions for PPSC, FPSC & NTS

Biology MCQs carry a reliable block of marks in PPSC, FPSC, NTS, ETEA, FGEI and one-paper tests. The question pool is limited and predictable: human body systems, vitamins and their deficiencies, blood groups, cell structure, and common diseases. This guide gives you 50 solved Biology MCQs with explanations — the highest-yield facts in one revision session.

How to use: Attempt each question on paper in under one minute, then read the explanation. Units, formulas and definitions repeat more than anything else in these papers.

Most Repeated Biology MCQs for PPSC, FPSC & NTS Topics

Human body systems — heart, lungs, kidneys, digestive system
Vitamins and deficiencies — A, C, D, K and their diseases
Blood groups — universal donor and recipient
Cell structure — nucleus, mitochondria, chloroplast
Common diseases — malaria, TB, AIDS and their causes
Plants — photosynthesis, transpiration, root absorption
Numbers to memorise — 206 bones, 46 chromosomes, 12–20 breaths

50 Solved MCQs

Q1. The basic structural and functional unit of life is:

A) Tissue

B) Cell

C) Organ

D) Organelle

Answer: B) Cell

Explanation: All living organisms are made of one or more cells.

Q2. The largest organ of the human body is:

A) Skin

B) Liver

C) Heart

D) Brain

Answer: A) Skin

Explanation: Skin covers about 2 m² and protects against infection and water loss.

Q3. Normal human body temperature is commonly taken as:

A) 35°C

B) 37°C

C) 39°C

D) 41°C

Answer: B) 37°C

Explanation: About 37°C (98.6°F) is the standard average.

Q4. The number of bones in an adult human skeleton is:

A) 186

B) 206

C) 196

D) 216

Answer: B) 206

Explanation: Babies have about 270 bones, many of which fuse to 206 in adults.

Q5. Which blood group is called the universal red-cell donor?

A) A positive

B) AB positive

C) B negative

D) O negative

Answer: D) O negative

Explanation: O negative red cells lack A/B antigens and the Rh factor.

Q6. Which vitamin deficiency causes night blindness?

A) Vitamin B

B) Vitamin C

C) Vitamin A

D) Vitamin D

Answer: C) Vitamin A

Explanation: Vitamin A is essential for rhodopsin, needed for vision in dim light.

Q7. Which vitamin deficiency causes rickets?

A) Vitamin A

B) Vitamin C

C) Vitamin K

D) Vitamin D

Answer: D) Vitamin D

Explanation: Vitamin D helps calcium absorption; deficiency softens bones.

Q8. The organ that pumps blood around the body is:

A) Heart

B) Kidney

C) Lungs

D) Liver

Answer: A) Heart

Explanation: The heart’s four chambers pump oxygenated and deoxygenated blood separately.

Q9. Photosynthesis mainly occurs in:

A) Chloroplasts

B) Roots

C) Stems

D) Nucleus

Answer: A) Chloroplasts

Explanation: Chloroplasts contain chlorophyll, which captures light energy.

Q10. The gas absorbed by plants during photosynthesis is:

A) Oxygen

B) Nitrogen

C) Carbon dioxide

D) Hydrogen

Answer: C) Carbon dioxide

Explanation: Plants take in CO₂ and release oxygen.

Q11. Which part of the plant absorbs water and minerals?

A) Root

B) Leaf

C) Stem

D) Flower

Answer: A) Root

Explanation: Root hairs provide a large surface area for absorption.

Q12. The study of heredity is called:

A) Ecology

B) Genetics

C) Botany

D) Zoology

Answer: B) Genetics

Explanation: Genetics examines how traits are passed from parents to offspring.

Q13. Blood is pumped from the heart to the lungs through the:

A) Aorta

B) Pulmonary artery

C) Vena cava

D) Coronary artery

Answer: B) Pulmonary artery

Explanation: The pulmonary artery carries deoxygenated blood to the lungs.

Q14. The functional unit of the kidney is the:

A) Neuron

B) Alveolus

C) Villus

D) Nephron

Answer: D) Nephron

Explanation: Each kidney contains about a million nephrons that filter blood.

Q15. The exchange of gases in the lungs takes place in the:

A) Bronchi

B) Alveoli

C) Trachea

D) Pleura

Answer: B) Alveoli

Explanation: Alveoli provide a huge thin surface for oxygen and CO₂ exchange.

Q16. Which cell organelle is known as the powerhouse of the cell?

A) Nucleus

B) Mitochondria

C) Ribosome

D) Golgi body

Answer: B) Mitochondria

Explanation: Mitochondria generate ATP through cellular respiration.

Q17. The number of chromosomes in a normal human body cell is:

A) 46

B) 23

C) 44

D) 48

Answer: A) 46

Explanation: 23 pairs — one from each parent.

Q18. Which hormone regulates blood sugar?

A) Thyroxine

B) Adrenaline

C) Testosterone

D) Insulin

Answer: D) Insulin

Explanation: Insulin from the pancreas lowers blood glucose.

Q19. Malaria is caused by:

A) A virus

B) A bacterium

C) A protozoan

D) A fungus

Answer: C) A protozoan

Explanation: Plasmodium, spread by the female Anopheles mosquito.

Q20. Tuberculosis is caused by:

A) A bacterium

B) A virus

C) A fungus

D) A protozoan

Answer: A) A bacterium

Explanation: Mycobacterium tuberculosis, commonly affecting the lungs.

Q21. Which blood vessels carry blood away from the heart?

A) Veins

B) Capillaries

C) Lymph vessels

D) Arteries

Answer: D) Arteries

Explanation: Arteries carry blood away; veins return it.

Q22. The largest gland in the human body is:

A) Pancreas

B) Liver

C) Thyroid

D) Salivary gland

Answer: B) Liver

Explanation: The liver performs over 500 functions, including bile production.

Q23. Which organ in the body produces insulin?

A) Pancreas

B) Liver

C) Kidney

D) Spleen

Answer: A) Pancreas

Explanation: Beta cells in the pancreas secrete insulin.

Q24. The process by which plants lose water vapour is:

A) Respiration

B) Photosynthesis

C) Transpiration

D) Digestion

Answer: C) Transpiration

Explanation: Water escapes through stomata in the leaves.

Q25. Which vitamin is essential for blood clotting?

A) Vitamin A

B) Vitamin C

C) Vitamin K

D) Vitamin E

Answer: C) Vitamin K

Explanation: Vitamin K is required for several clotting factors.

Q26. Enzymes are chemically:

A) Carbohydrates

B) Lipids

C) Minerals

D) Proteins

Answer: D) Proteins

Explanation: Enzymes are biological catalysts made of protein.

Q27. The human brain is protected by the:

A) Ribs

B) Vertebrae

C) Cranium

D) Sternum

Answer: C) Cranium

Explanation: The skull (cranium) encloses and protects the brain.

Q28. Which part of the eye controls the amount of light entering?

A) Retina

B) Iris

C) Cornea

D) Lens

Answer: B) Iris

Explanation: The iris adjusts the pupil size to regulate light.

Q29. The unit of heredity is the:

A) Chromosome

B) Gene

C) Nucleus

D) Allele

Answer: B) Gene

Explanation: A gene is a segment of DNA that codes for a trait.

Q30. Blood cells that fight infection are:

A) Red blood cells

B) Platelets

C) Plasma

D) White blood cells

Answer: D) White blood cells

Explanation: White blood cells (leucocytes) defend the body against pathogens.

Q31. Which gas do humans exhale in the largest amount?

A) Oxygen

B) Nitrogen

C) Carbon dioxide

D) Water vapour

Answer: B) Nitrogen

Explanation: Exhaled air is still mostly nitrogen — around 78%.

Q32. AIDS is caused by:

A) A bacterium

B) A virus

C) A protozoan

D) A fungus

Answer: B) A virus

Explanation: HIV attacks the immune system, particularly CD4 cells.

Q33. The smallest bone in the human body is in the:

A) Ear

B) Finger

C) Toe

D) Nose

Answer: A) Ear

Explanation: The stapes in the middle ear is the smallest bone.

Q34. Which organ filters waste products from the blood?

A) Kidneys

B) Heart

C) Lungs

D) Stomach

Answer: A) Kidneys

Explanation: Kidneys remove urea and excess salts through urine.

Q35. Insulin deficiency causes:

A) Anaemia

B) Diabetes

C) Rickets

D) Scurvy

Answer: B) Diabetes

Explanation: Without insulin, blood glucose rises — diabetes mellitus.

Q36. Which type of blood group is the universal recipient?

A) AB positive

B) A negative

C) O negative

D) B positive

Answer: A) AB positive

Explanation: AB positive red cells have no antibodies against A, B or Rh.

Q37. The main function of red blood cells is to:

A) Fight infection

B) Clot blood

C) Digest food

D) Carry oxygen

Answer: D) Carry oxygen

Explanation: Haemoglobin in red cells binds oxygen.

Q38. Which vitamin deficiency causes scurvy?

A) Vitamin C

B) Vitamin A

C) Vitamin B12

D) Vitamin K

Answer: A) Vitamin C

Explanation: Vitamin C is needed for collagen production.

Q39. The human digestive system begins at the:

A) Stomach

B) Oesophagus

C) Small intestine

D) Mouth

Answer: D) Mouth

Explanation: Digestion starts with chewing and salivary amylase.

Q40. Both lungs are protected by the:

A) Cranium

B) Pelvis

C) Spine

D) Ribs

Answer: D) Ribs

Explanation: The rib cage encloses the heart and lungs.

Q41. Which part of the cell controls its activities?

A) Cytoplasm

B) Cell membrane

C) Nucleus

D) Vacuole

Answer: C) Nucleus

Explanation: The nucleus contains DNA and directs cellular activity.

Q42. The process of cell division that produces gametes is:

A) Mitosis

B) Fusion

C) Fission

D) Meiosis

Answer: D) Meiosis

Explanation: Meiosis halves the chromosome number.

Q43. Which animal tissue connects and supports body parts?

A) Connective

B) Epithelial

C) Muscle

D) Nervous

Answer: A) Connective

Explanation: Bone, cartilage and blood are connective tissues.

Q44. The largest artery in the human body is the:

A) Aorta

B) Pulmonary artery

C) Carotid artery

D) Femoral artery

Answer: A) Aorta

Explanation: The aorta carries oxygenated blood from the left ventricle.

Q45. Which nutrient is the body’s main quick energy source?

A) Protein

B) Fat

C) Carbohydrate

D) Vitamin

Answer: C) Carbohydrate

Explanation: Carbohydrates break down quickly into glucose.

Q46. The breathing rate of a healthy adult at rest is about:

A) 6–8 per minute

B) 30–40 per minute

C) 12–20 per minute

D) 50–60 per minute

Answer: C) 12–20 per minute

Explanation: Normal adult resting rate is roughly 12–20 breaths per minute.

Q47. The outer layer of the skin is called the:

A) Dermis

B) Hypodermis

C) Follicle

D) Epidermis

Answer: D) Epidermis

Explanation: The epidermis is the protective outer layer.

Q48. Which organ stores bile?

A) Liver

B) Pancreas

C) Gall bladder

D) Stomach

Answer: C) Gall bladder

Explanation: Bile is produced in the liver and stored in the gall bladder.

Q49. Antibiotics are effective against:

A) Viruses

B) All pathogens

C) Bacteria

D) Fungi only

Answer: C) Bacteria

Explanation: Antibiotics target bacterial structures and do not work on viruses.

Q50. The pigment responsible for skin colour is:

A) Chlorophyll

B) Haemoglobin

C) Melanin

D) Carotene

Answer: C) Melanin

Explanation: Melanin protects the skin from UV radiation.

Most Repeated Biology MCQs for PPSC, FPSC & NTS Topics

50 Solved MCQs

Q1. The basic structural and functional unit of life is:

Q2. The largest organ of the human body is:

Q3. Normal human body temperature is commonly taken as:

Q4. The number of bones in an adult human skeleton is:

Q5. Which blood group is called the universal red-cell donor?

Q6. Which vitamin deficiency causes night blindness?

Q7. Which vitamin deficiency causes rickets?

Q8. The organ that pumps blood around the body is:

Q9. Photosynthesis mainly occurs in:

Q10. The gas absorbed by plants during photosynthesis is:

Q11. Which part of the plant absorbs water and minerals?

Q12. The study of heredity is called:

Q13. Blood is pumped from the heart to the lungs through the:

Q14. The functional unit of the kidney is the:

Q15. The exchange of gases in the lungs takes place in the:

Q16. Which cell organelle is known as the powerhouse of the cell?

Q17. The number of chromosomes in a normal human body cell is:

Q18. Which hormone regulates blood sugar?

Q19. Malaria is caused by:

Q20. Tuberculosis is caused by:

Q21. Which blood vessels carry blood away from the heart?

Q22. The largest gland in the human body is:

Q23. Which organ in the body produces insulin?

Q24. The process by which plants lose water vapour is:

Q25. Which vitamin is essential for blood clotting?

Q26. Enzymes are chemically:

Q27. The human brain is protected by the:

Q28. Which part of the eye controls the amount of light entering?

Q29. The unit of heredity is the:

Q30. Blood cells that fight infection are:

Q31. Which gas do humans exhale in the largest amount?

Q32. AIDS is caused by:

Q33. The smallest bone in the human body is in the:

Q34. Which organ filters waste products from the blood?

Q35. Insulin deficiency causes:

Q36. Which type of blood group is the universal recipient?

Q37. The main function of red blood cells is to:

Q38. Which vitamin deficiency causes scurvy?

Q39. The human digestive system begins at the:

Q40. Both lungs are protected by the:

Q41. Which part of the cell controls its activities?

Q42. The process of cell division that produces gametes is:

Q43. Which animal tissue connects and supports body parts?

Q44. The largest artery in the human body is the:

Q45. Which nutrient is the body’s main quick energy source?

Q46. The breathing rate of a healthy adult at rest is about:

Q47. The outer layer of the skin is called the:

Q48. Which organ stores bile?

Q49. Antibiotics are effective against:

Q50. The pigment responsible for skin colour is:

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