SSC CGL, Railway Exams (RRB NTPC/Group D) MCQs

Q1. Which gland is called the "master gland"?

a) Thyroid

b) Pituitary

c) Adrenal

d) Pancreas

Answer: b) Pituitary (Controls other endocrine glands)

Q2. Hemoglobin is a protein found in:

a) WBCs

b) Platelets

c) RBCs

d) Plasma

Answer: c) RBCs (Binds oxygen for transport)

Q3. Which vitamin is synthesized in the skin under sunlight?

a) Vitamin A

b) Vitamin D

c) Vitamin K

d) Vitamin C

Answer: b) Vitamin D (Prevents rickets & osteoporosis)

Q4. Largest organ in the human body is:

a) Liver

b) Skin

c) Brain

d) Lungs

Answer: b) Skin (Covers ~2 m², protects against pathogens)

Q5. Bile is produced by:

a) Pancreas

b) Stomach

c) Liver

d) Gallbladder

Answer: c) Liver (Stored in gallbladder, emulsifies fats)

Q6. Which part of the brain controls balance?

a) Cerebrum

b) Cerebellum

c) Medulla

d) Hypothalamus

Answer: b) Cerebellum (Coordinates movement & posture)

Q7. Normal human blood pressure is:

a) 120/80 mmHg

b) 140/90 mmHg

c) 100/60 mmHg

d) 160/100 mmHg

Answer: a) 120/80 mmHg (Systolic/diastolic pressure)

Q8. Smallest bone in the human body is:

a) Femur

b) Stapes

c) Tibia

d) Humerus

Answer: b) Stapes (Located in the middle ear)

Q9. Insulin is secreted by:

a) Liver

b) Pancreas

c) Thyroid

d) Adrenal

Answer: b) Pancreas (Beta cells in Islets of Langerhans)

Q10. Which blood group is a universal donor?

a) A

b) B

c) AB

d) O

Answer: d) O (No antigens on RBCs)

Q11. Photosynthesis occurs in which cell organelle?

a) Mitochondria

b) Chloroplast

c) Nucleus

d) Ribosome

Answer: b) Chloroplast (Contains chlorophyll)

Q12. The "powerhouse of the cell" is:

a) Golgi body

b) Mitochondria

c) Lysosome

d) Nucleus

Answer: b) Mitochondria (Produces ATP via respiration)

Q13. Which plant hormone promotes growth?

a) Abscisic acid

b) Auxin

c) Cytokinin

d) Ethylene

Answer: b) Auxin (Stimulates cell elongation)

Q14. Transpiration occurs through:

a) Roots

b) Stomata

c) Flowers

d) Xylem

Answer: b) Stomata (Pores on leaves for gas exchange)

Q15. Nitrogen-fixing bacteria are found in roots of:

a) Wheat

b) Rice

c) Legumes

d) Maize

Answer: c) Legumes (Symbiosis with Rhizobium)

Q16. Which disease is caused by Vitamin C deficiency?

a) Scurvy

b) Rickets

c) Beriberi

d) Night blindness

Answer: a) Scurvy (Bleeding gums, weak immunity)

Q17. Dengue is transmitted by:

a) Aedes mosquito

b) Anopheles mosquito

c) Housefly

d) Tsetse fly

Answer: a) Aedes mosquito (Also spreads Zika & Chikungunya)

Q18. BCG vaccine is for:

a) Tuberculosis

b) Polio

c) Hepatitis B

d) Tetanus

Answer: a) Tuberculosis (Bacillus Calmette-Guérin vaccine)

Q19. DNA structure was discovered by:

a) Darwin

b) Mendel

c) Watson & Crick

d) Pasteur

Answer: c) Watson & Crick (Double helix model, 1953)

Q20. The father of genetics is:

a) Lamarck

b) Gregor Mendel

c) Huxley

d) Hooke

Answer: b) Gregor Mendel (Pea plant experiments)

Q21. Ozone layer protects Earth from:

a) UV rays

b) IR rays

c) X-rays

d) Gamma rays

Answer: a) UV rays (Prevents skin cancer & mutations)

Q22. The "Greenhouse gas" is:

a) Oxygen

b) Nitrogen

c) Carbon dioxide

d) Hydrogen

Answer: c) Carbon dioxide (Traps heat, causes global warming)

Q23. Which enzyme digests proteins in the stomach?

a) Amylase

b) Lipase

c) Pepsin

d) Trypsin

Answer: c) Pepsin (Works in acidic pH, breaks proteins into peptides)

Q24. Hormone responsible for the "fight or flight" response is:

a) Insulin

b) Adrenaline

c) Thyroxine

d) Estrogen

Answer: b) Adrenaline (Secreted by adrenal glands during stress)

Q25. Which part of the eye controls light entry?

a) Retina

b) Iris

c) Cornea

d) Optic nerve

Answer: b) Iris (Adjusts pupil size to regulate light)

Q26. The universal blood recipient group is:

a) A

b) B

c) AB

d) O

Answer: c) AB (Can receive blood from any group)

Q27. Deficiency of iodine causes:

a) Goiter

b) Anemia

c) Scurvy

d) Rickets

Answer: a) Goiter (Enlarged thyroid gland due to lack of thyroxine)

Q28. The process of water movement through a plant is called:

a) Transpiration

b) Photosynthesis

c) Osmosis

d) Capillary action

Answer: a) Transpiration (Water loss from leaves creates suction pull)

Q29. Which plant part is modified in potatoes?

a) Root

b) Stem

c) Leaf

d) Flower

Answer: b) Stem (Tuber stores food underground)

Q30. Vernalization is related to:

a) Seed germination

b) Flowering induction by cold

c) Leaf fall

d) Fruit ripening

Answer: b) Flowering induction by cold (Example: Winter wheat)

Q31. Which disease is caused by a vitamin B1 deficiency?

a) Scurvy

b) Beriberi

c) Pellagra

d) Night blindness

Answer: b) Beriberi (Affects nerves and heart, common in polished rice diets)

Q32. HIV attacks which cells?

a) RBCs

b) Platelets

c) Helper T-cells (CD4)

d) B-cells

Answer: c) Helper T-cells (CD4) (Weakens the immune system)

Q33. The theory of natural selection was proposed by:

a) Gregor Mendel

b) Charles Darwin

c) Lamarck

d) Watson & Crick

Answer: b) Charles Darwin (Origin of Species, 1859)

Q34. A human male has which sex chromosomes?

a) XX

b) XY

c) YY

d) XO

Answer: b) XY (Female: XX)

Q35. The ozone layer is found in which atmospheric layer?

a) Troposphere

b) Stratosphere

c) Mesosphere

d) Thermosphere

Answer: b) Stratosphere (Blocks UV-B radiation)

Q35. The "Greenhouse effect" is primarily caused by:

a) Oxygen

b) Nitrogen

c) Carbon dioxide

d) Hydrogen

Answer: c) Carbon dioxide (Traps infrared radiation

Q36. Which part of the digestive system absorbs most nutrients?

a) Stomach

b) Small intestine

c) Large intestine

d) Esophagus

Answer: b) Small intestine (Villi increase surface area for absorption)

Q37. The hormone that regulates blood calcium levels is:

a) Insulin

b) Thyroxine

c) Parathormone

d) Adrenaline

Answer: c) Parathormone (Secreted by parathyroid glands)

Q38. Which blood vessels carry oxygenated blood from the lungs to the heart?

a) Pulmonary arteries

b) Pulmonary veins

c) Aorta

d) Coronary arteries

Answer: b) Pulmonary veins (Only veins carrying oxygen-rich blood)

Q39. The functional unit of the kidney is:

a) Neuron

b) Nephron

c) Alveoli

d) Hepatocyte

Answer: b) Nephron (Filters blood and forms urine)

Q40. Which vitamin is essential for vision in dim light?

a) Vitamin A

b) Vitamin B12

c) Vitamin C

d) Vitamin D

Answer: a) Vitamin A (Deficiency causes night blindness)

Q41. The process of water absorption by plant roots is called:

a) Transpiration

b) Osmosis

c) Photosynthesis

d) Respiration

Answer: b) Osmosis (Passive movement of water)

Q42. Which plant hormone inhibits growth?

a) Auxin

b) Gibberellin

c) Abscisic acid

d) Cytokinin

Answer: c) Abscisic acid (Stress hormone, closes stomata)

Q43. Edible part of a coconut is:

a) Endosperm

b) Embryo

c) Seed coat

d) Fruit wall

Answer: a) Endosperm (Liquid or solid nutritive tissue)

Q44. Which disease is transmitted by the Anopheles mosquito?

a) Dengue

b) Malaria

c) Chikungunya

d) Yellow fever

Answer: b) Malaria (Caused by Plasmodium parasite)

Q45. The vaccine for polio was developed by:

a) Louis Pasteur

b) Jonas Salk

c) Robert Koch

d) Alexander Fleming

Answer: b) Jonas Salk (Inactivated polio vaccine, 1955)

Q46. The term "mutation" was coined by:

a) Charles Darwin

b) Gregor Mendel

c) Hugo de Vries

d) Thomas Hunt Morgan

Answer: c) Hugo de Vries (Studied mutations in evening primrose)

Q47. Sex of a child is determined by chromosomes from the:

a) Mother

b) Father

c) Both parents equally

d) Mitochondria

Answer: b) Father (Sperm carries either X or Y chromosome)

Q48. What is the pH range of human blood?

a) 6.8-7.0

b) 7.3-7.5

c) 7.35-7.45

d) 8.0-8.5

Answer: c) 7.35-7.45 (Slightly alkaline)

Q49. Which organ produces bile?

a) Pancreas

b) Gallbladder

c) Liver

d) Stomach

Answer: c) Liver (Gallbladder stores bile)

Q50. Smallest bone in the human body is located in the:

a) Hand

b) Ear

c) Foot

d) Nose

Answer: b) Ear (Stapes in middle ear)