Looking for reliable SEBA Class 10 Science Chapter 6 MCQ solutions for the 2026–27 academic session? Access complete multiple-choice questions with correct option choices, detailed answers, and quick revision notes to boost your score in the upcoming HSLC board exams.
MCQ
Q1. Which of the following is not a life process?
A) Respiration
B) Reproduction
C) Transportation
D) Digestion
Answer: B) Reproduction
Explanation: Reproduction is necessary for the continuation of a species, but it is not essential for the survival of an individual organism.
Q2. Which statement about living organisms is true?
A) All show visible movement
B) Life depends on molecular movement inside the body
C) Viruses are definitely living
D) Only plants are alive
Answer: B) Life depends on molecular movement inside the body
Explanation: Continuous invisible molecular movement is essential for repairing, maintaining, and exchanging materials inside living cells.
Q3. Life processes help in:
A) Reproduction
B) Maintenance of life
C) Photosynthesis only
D) Movement only
Answer: B) Maintenance of life Explanation: Life processes are the basic functions that continuously maintain tissue repair, energy supply, and metabolic functions required to keep an organism alive.
Q4. Which process provides energy to living organisms?
A) Digestion
B) Photosynthesis
C) Respiration
D) Transportation
Answer: C) Respiration
Explanation: Respiration is the cellular process of breaking down nutrients like glucose to release energy in the form of ATP.
Q5. Organisms that make their own food are called:
A) Heterotrophs
B) Autotrophs
C) Parasites
D) Saprotrophs
Answer: B) Autotrophs Explanation: Autotrophs synthesize their own organic nutrients from simple inorganic substances like carbon dioxide and water using light energy.
Q6. The energy needed for photosynthesis comes from:
A) Soil
B) Water
C) Sunlight
D) Air
Answer: C) Sunlight
Explanation: Chlorophyll traps radiant solar energy from sunlight and converts it into chemical energy during photosynthesis.
Q7. What is the word equation for photosynthesis?
A) CO₂ + O₂ → Glucose + Water
B) Glucose + O₂ → CO₂ + Water
C) CO₂ + H₂O → Glucose + O₂
D) H₂O + O₂ → Glucose + CO₂
Answer: C) CO₂ + H₂O → Glucose + O₂
Explanation: Carbon dioxide and water combine in the presence of sunlight and chlorophyll to form glucose and release oxygen gas.
Q8. The green pigment in plants needed for photosynthesis is:
A) Xylem
B) Chlorophyll
C) Phloem
D) Hemoglobin
Answer: B) Chlorophyll Explanation: Chlorophyll is the green pigment located within chloroplasts that absorbs sunlight required for photosynthesis.
Q9. Carbon dioxide enters the leaf through:
A) Cuticle
B) Stomata
C) Root hairs
D) Veins
Answer: B) Stomata Explanation: Stomata are tiny pores present on the surface of leaves through which gaseous exchange takes place.
SEBA Class 10 Science Chapter 6 Objective Questions
Q10. The opening and closing of stomata are controlled by:
A) Guard cells
B) Chloroplasts
C) Xylem vessels
D) Root hairs
Answer: A) Guard cells
Explanation: Guard cells swell when water flows into them, causing the stomatal pore to open, and shrink when water moves out, causing the pore to close.
Q11. Organisms that depend on others for food are:
A) Autotrophs
B) Heterotrophs
C) Chemotrophs
D) Phototrophs
Answer: B) Heterotrophs
Explanation: Heterotrophs are organisms that cannot synthesize their own food and must rely on consuming other plants or animals for nutrition.
Q12. Amoeba takes in food through:
A) Cilia
B) Flagella
C) Pseudopodia
D) Tentacles
Answer: C) Pseudopodia Explanation: Amoeba uses finger-like temporary extensions called pseudopodia to engulf food particles into a food vacuole.
Q13. The enzyme in saliva that breaks down starch is:
A) Pepsin
B) Trypsin
C) Amylase
D) Lipase
Answer: C) Amylase Explanation: Salivary amylase breaks down complex starch molecules into simple sugars like maltose in the mouth.
Q14. Hydrochloric acid (HCl) in the stomach helps in:
A) Neutralizing acid
B) Digesting fat
C) Killing germs and creating acidic medium
D) Producing bile
Answer: C) Killing germs and creating acidic medium Explanation: Hydrochloric acid kills harmful bacteria that enter with food and provides the acidic environment necessary for the digestive enzyme pepsin to function.
Q15. Bile juice is produced by:
A) Stomach
B) Liver
C) Pancreas
D) Small intestine
Answer: B) Liver
Explanation: Bile juice is secreted by the liver and stored in the gallbladder before being released into the small intestine.
Q16. Bile helps in:
A) Digestion of protein
B) Emulsification of fats
C) Breaking down sugar
D) Absorption of vitamins
Answer: B) Emulsification of fats
Explanation: Bile breaks down large fat globules into smaller emulsified droplets, making it easier for lipase enzymes to digest them.
Q17. Finger-like projections in the small intestine are called:
A) Cilia
B) Villi
C) Microvilli
D) Papillae
Answer: B) Villi
Explanation: Villi are tiny finger-like projections in the inner lining of the small intestine that increase the surface area for maximum nutrient absorption into the blood.
Q18. In respiration, glucose is broken down to release:
A) Oxygen
B) Energy
C) Protein
D) Nitrogen
Answer: B) Energy
Explanation: Respiration is a biochemical process in which glucose molecules are oxidized inside cells to release energy for metabolic functions.
Q19. The energy released during respiration is stored in:
A) RNA
B) DNA
C) ATP
D) ADP
Answer: C) ATP
Explanation: Energy released during cellular respiration is stored in molecules of ATP (Adenosine Triphosphate), which acts as the energy currency of the cell.
HSLC Science Chapter 6 MCQ Notes
Q20. In yeast, anaerobic respiration produces:
A) Lactic acid
B) Alcohol and CO₂
C) Oxygen and water
D) Glucose
Answer: B) Alcohol and CO₂
Explanation: During alcoholic fermentation, yeast breaks down glucose in the absence of oxygen to form ethanol (alcohol), carbon dioxide, and a small amount of energy.
Q21. The exchange of gases in humans takes place in:
A) Bronchi
B) Alveoli
C) Trachea
D) Nose
Answer: B) Alveoli
Explanation: Alveoli are tiny, balloon-like air sacs wrapped in blood capillaries where oxygen diffuses into the blood and carbon dioxide diffuses out.
Q22. Hemoglobin is present in:
A) White blood cells
B) Platelets
C) Plasma
D) Red blood cells
Answer: D) Red blood cells
Explanation: Hemoglobin is a red iron-containing pigment present in red blood cells that binds with oxygen and transports it to body cells.
Q23. Which chamber of the heart pumps blood to the whole body?
A) Left atrium
B) Right atrium
C) Left ventricle
D) Right ventricle
Answer: C) Left ventricle
Explanation: The left ventricle has thick muscular walls to pump oxygenated blood under high pressure through the aorta to the entire body.
Q24. The normal blood pressure in humans is:
A) 120/80 mm Hg
B) 100/60 mm Hg
C) 140/100 mm Hg
D) 90/70 mm Hg
Answer: A) 120/80 mm Hg
Explanation: Normal human blood pressure consists of a systolic pressure of 120 mm Hg and a diastolic pressure of 80 mm Hg.
Q25. Blood vessels that carry blood away from the heart are:
A) Veins
B) Arteries
C) Capillaries
D) Lymph vessels
Answer: B) Arteries
Explanation: Arteries carry blood away from the heart to various body organs, whereas veins bring blood back toward the heart.
Q26. The upward movement of water in plants occurs through:
A) Phloem
B) Xylem
C) Stomata
D) Roots only
Answer: B) Xylem
Explanation: Xylem tissue conducts water and dissolved minerals upward from the roots to the stems and leaves of a plant.
Q27. Transport of food in plants is called:
A) Transpiration
B) Translocation
C) Photosynthesis
D) Respiration
Answer: B) Translocation
Explanation: Translocation is the active movement of soluble products of photosynthesis (sucrose) through phloem tissue to various plant parts.
Q28. The energy required for translocation in plants comes from:
A) Sunlight
B) Diffusion
C) ATP
D) Gravity
Answer: C) ATP
Explanation: Translocation in phloem is an active transport process that utilizes metabolic energy stored in ATP molecules.
Q29. The structural and functional unit of the kidney is:
A) Neuron
B) Nephron
C) Alveolus
D) Glomerulus
Answer: B) Nephron
Explanation: Nephrons are the microscopic filtering units inside the kidneys responsible for removing waste products and forming urine.
SEBA Class 10 Science Chapter 6 Multiple Choice Questions
Q30. In dialysis, waste products are removed from blood by:
A) Filtration through a semi-permeable membrane
B) Heating the blood
C) Adding chemicals
D) Freezing
Answer: A) Filtration through a semi-permeable membrane
Explanation: An artificial kidney (dialyzer) contains selective semi-permeable tubes that allow nitrogenous wastes to pass from the blood into a dialyzing fluid by diffusion.
Q31. What is the purpose of keeping the variegated plant in a dark room for three days?
A) To remove chlorophyll
B) To decolorize leaves
C) To use up stored starch
D) To make leaves dry
Answer: C) To use up stored starch
Explanation: Keeping the plant in the dark prevents photosynthesis, forcing the plant to consume all its previously stored starch so that it becomes destarched before the experiment.
Q32. Why is the leaf boiled in water during the photosynthesis experiment?
A) To make it soft
B) To remove starch
C) To remove chlorophyll
D) To dry the leaf
Answer: A) To make it soft
Explanation: Boiling the leaf in water breaks down cell membranes and stops all enzymatic activity, making the leaf soft and permeable to iodine solution.
Q33. Why is the leaf placed in boiling alcohol after boiling in water?
A) To remove starch
B) To remove chlorophyll
C) To kill the leaf
D) To make it green
Answer: B) To remove chlorophyll
Explanation: Alcohol dissolves and removes green chlorophyll pigment from the leaf, decolorizing it so that any color change during the iodine test can be observed clearly.
Q34. What is the role of iodine in the experiment?
A) Tests for protein
B) Tests for glucose
C) Tests for starch
D) Tests for oxygen
Answer: C) Tests for starch
Explanation: Iodine solution serves as an indicator that specifically turns blue-black in the presence of starch, confirming that photosynthesis has taken place.
Q35. Which part of the variegated leaf turns blue-black with iodine?
A) Non-green area
B) Green area
C) Entire leaf
D) Midrib only
Answer: B) Green area
Explanation: Only the green portions contain chlorophyll to perform photosynthesis and produce starch, causing those specific areas to turn blue-black with iodine.
Q36. The result of this experiment shows that:
A) Chlorophyll is not needed for photosynthesis
B) Sunlight is not needed
C) Only green parts (with chlorophyll) make starch
D) Water stops starch formation
Answer: C) Only green parts (with chlorophyll) make starch
Explanation: Because only the green parts of the leaf test positive for starch, the experiment proves that chlorophyll is essential for photosynthesis.
Q37. What is the function of potassium hydroxide in this experiment?
A) Absorbs oxygen
B) Absorbs water vapor
C) Absorbs carbon dioxide
D) Releases carbon dioxide
Answer: C) Absorbs carbon dioxide
Explanation: Potassium hydroxide (KOH) chemically absorbs carbon dioxide inside the glass jar, creating a CO₂-free environment for the experimental setup.
Q38. Why are the plants kept in the dark for three days before the experiment?
A) To remove chlorophyll
B) To use up stored starch
C) To kill the plant
D) To increase photosynthesis
Answer: B) To use up stored starch
Explanation: Placed in darkness, the plant cannot synthesize new food and utilizes its existing starch reserves, ensuring that any starch detected later is synthesized during the experiment.
Q39. What is used to make the setup air-tight?
A) Alcohol
B) Vaseline
C) Wax
D) Oil
Answer: B) Vaseline
Explanation: Vaseline is applied around the rim and connections of the glass apparatus to seal all gaps and prevent surrounding air from leaking into the setup.
Class 10 Science Chapter 6 MCQ Question Answer SEBA 2026-27
Q40. What is observed in the leaf of the plant kept without CO₂?
A) No starch formed
B) More starch formed
C) Leaf turns red
D) Chlorophyll removed
Answer: A) No starch formed
Explanation: Without carbon dioxide, the leaf cannot carry out photosynthesis to produce glucose or starch, so it does not turn blue-black when tested with iodine.
Q41. The conclusion of this activity is that:
A) CO₂ is not needed for photosynthesis
B) CO₂ is essential for photosynthesis
C) Oxygen is the main raw material
D) Chlorophyll is not important
Answer: B) CO₂ is essential for photosynthesis
Explanation: The experimental setup without carbon dioxide fails to produce starch, proving that carbon dioxide is a necessary raw material for photosynthesis.
Q42. What enzyme is present in saliva?
A) Pepsin
B) Lipase
C) Amylase
D) Trypsin
Answer: C) Amylase
Explanation: Salivary amylase (ptyalain) is secreted by the salivary glands to initiate the chemical digestion of complex carbohydrates into simpler sugars.
Q43. Which test tube will show a blue-black color with iodine?
A) Test tube A (with saliva)
B) Test tube B (without saliva)
C) Both A and B
D) None
Answer: B) Test tube B (without saliva)
Explanation: Test tube B retains its starch unchanged because no saliva was added to break it down, allowing iodine to react with the starch and give a positive blue-black color.
Q44. Why does test tube A not show blue-black color?
A) Starch converted to sugar by saliva
B) Iodine lost color
C) No reaction occurred
D) Alcohol destroyed starch
Answer: A) Starch converted to sugar by saliva
Explanation: Salivary amylase breaks down the starch into simple sugars (like maltose), leaving no intact starch for the iodine solution to turn blue-black.
Q45. What does this experiment prove?
A) Saliva digests proteins
B) Saliva digests starch into sugars
C) Saliva contains acids
D) Saliva is colorless
Answer: B) Saliva digests starch into sugars
Explanation: Since starch disappears only in the presence of saliva, the experiment demonstrates that saliva contains an enzyme capable of digesting complex starch into simpler sugars.
Q46. Why does lime water turn milky when air is blown through it?
A) Due to oxygen
B) Due to carbon dioxide
C) Due to nitrogen
D) Due to water vapor
Answer: B) Due to carbon dioxide
Explanation: Carbon dioxide gas reacts chemically with clear lime water (calcium hydroxide) to produce an insoluble white precipitate of calcium carbonate, making the solution look milky.
Q47. When you blow air from your mouth, lime water turns milky faster because:
A) Exhaled air has more CO₂
B) Exhaled air has less CO₂
C) Exhaled air is cold
D) Exhaled air is dry
Answer: A) Exhaled air has more CO₂
Explanation: Cellular respiration in human tissues generates carbon dioxide, making exhaled air contain a much higher concentration of CO₂ than surrounding atmospheric air.
Q48. The milky appearance is due to formation of:
A) Calcium oxide
B) Calcium carbonate
C) Carbonic acid
D) Hydrogen peroxide
Answer: B) Calcium carbonate
Explanation: The chemical reaction between calcium hydroxide [Ca(OH)₂] in lime water and carbon dioxide (CO₂) produces insoluble calcium carbonate (CaCO₃) crystals suspended in water.
Q49. In the yeast experiment, what gas is released during fermentation?
A) Oxygen
B) Carbon dioxide
C) Nitrogen
D) Hydrogen
Answer: B) Carbon dioxide
Explanation: Yeast performs anaerobic respiration (fermentation) to break down sugar into ethanol and carbon dioxide gas as a byproduct.
SEBA Class 10 Science Chapter 6 MCQ Solutions
Q50. What change is observed in the lime water?
A) Turns blue
B) Turns milky
C) Turns pink
D) Remains clear
Answer: B) Turns milky
Explanation: The carbon dioxide gas released during yeast fermentation passes into the connected tube of lime water, reacting with it to form a milky calcium carbonate precipitate.
Q51. What does this experiment show?
A) Oxygen is produced during fermentation
B) CO₂ is produced during fermentation
C) Water is produced during fermentation
D) No gas is released
Answer: B) CO₂ is produced during fermentation
Explanation: The gas released during yeast fermentation turns lime water milky, which proves that carbon dioxide is generated during the process.
Q52. Fish take in oxygen through:
A) Mouth
B) Gills
C) Skin
D) Fins
Answer: B) Gills
Explanation: Gills are specialized respiratory organs in fish that absorb dissolved oxygen directly from water passing over their vascular membranes.
Q53. When fish open their mouths, water enters and passes through:
A) Lungs
B) Gill slits
C) Air sacs
D) Fins
Answer: B) Gill slits
Explanation: Water taken in through the mouth is forced past the gill slits, where oxygen is extracted into the bloodstream before the water is expelled.
Q54. The number of mouth openings in fish per minute is:
A) Less than humans
B) More than humans
C) Equal to humans
D) Random
Answer: B) More than humans
Explanation: The concentration of dissolved oxygen in water is much lower than in air, so fish must pump water and open their mouths at a faster rate than human breathing to meet their oxygen needs.
Q55. Coordination between mouth and gill-slits ensures:
A) Rapid movement
B) Continuous water flow over gills
C) Breathing through skin
D) Respiration stops
Answer: B) Continuous water flow over gills
Explanation: Rhythmic opening and closing of the mouth and gill covers maintains a unidirectional, uninterrupted current of oxygen-rich water over the gill filaments.
Q56. What is the function of hemoglobin?
A) Fights infection
B) Carries oxygen
C) Helps clotting
D) Transports hormones
Answer: B) Carries oxygen
Explanation: Hemoglobin is an iron-rich respiratory pigment in red blood cells that binds reversibly with oxygen in the lungs and delivers it to body tissues.
Q57. Normal hemoglobin content in human adults is about:
A) 2–4 g/dL
B) 6–8 g/dL
C) 12–16 g/dL
D) 18–20 g/dL
Answer: C) 12–16 g/dL
Explanation: The healthy reference range for hemoglobin in human adults typically averages around 12 to 16 grams per deciliter of blood.
Q58. Hemoglobin levels are generally:
A) Higher in women
B) Higher in men
C) Same in both
D) Absent in children
Answer: B) Higher in men
Explanation: Higher levels of anabolic hormones like testosterone in males stimulate greater red blood cell production, resulting in higher average hemoglobin concentration.
Q59. The difference in hemoglobin between males and females is mainly due to:
A) Hormonal factors
B) Blood pressure
C) Age
D) Diet only
Answer: A) Hormonal factors
Explanation: Differences in androgenic hormones between sexes influence erythropoiesis (red blood cell formation), leading to higher baseline hemoglobin in males.
Q60. In the transpiration experiment, which setup shows water droplets on the plastic cover?
A) Pot with stick
B) Pot with plant
C) Both pots
D) None
Answer: B) Pot with plant
Explanation: Only the pot with the living plant loses water through leaf stomata via transpiration, which condenses as visible droplets on the inside of the plastic enclosure.
🔬 Updated MCQ Guide Notice: This page features a full list of SEBA Class 10 Science Chapter 6 Multiple Choice Questions (MCQs) with correct options and step-by-step explanations, fully updated for the 2026–27 academic session according to the latest revised Assam Board syllabus.
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