Assertion and reason questions Class 10 Science: life process
Are you preparing for your Class 10 Science exam and looking for the most important Assertion and Reason questions from the chapter Life Processes? You’re in the right place!
In this post, we’ve compiled a set of exam-focused Assertion and Reason questions based on key topics like nutrition, respiration, transportation, and excretion—all aligned with the latest CBSE Class 10 syllabus (2025).
These questions are designed to:
- Strengthen your conceptual understanding
- Help you practice higher-order thinking skills (HOTS)
- Improve your performance in MCQ-based board exams
Choose the correct option:
(A) Both Assertion (A) and Reason (R) are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
1.
A: Green plants are autotrophs.
R: They synthesize their own food using carbon dioxide and water in the presence of sunlight.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
2.
A: Heterotrophic organisms depend directly or indirectly on autotrophs.
R: Heterotrophs can prepare their own food.
✅ Answer: (C) A is true but R is false.
3.
A: Photosynthesis occurs only in chlorophyll-containing cells.
R: Chlorophyll absorbs sunlight required for photosynthesis.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
4.
A: Saliva contains enzymes that digest carbohydrates.
R: Salivary amylase breaks down starch into maltose.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
5.
A: Pepsin in the stomach breaks down fats into fatty acids.
R: Pepsin is a proteolytic enzyme active in acidic medium.
✅ Answer: (C) A is false but R is true.
6.
A: During vigorous exercise, muscle cells may respire anaerobically.
R: Anaerobic respiration provides quick energy without using oxygen.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
7.
A: Aerobic respiration produces more energy than anaerobic respiration.
R: Complete oxidation of glucose occurs in aerobic respiration.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
8.
A: Lungs are the primary organs for gaseous exchange in humans.
R: They have alveoli with a large surface area and rich blood supply.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
9.
A: Anaerobic respiration occurs in mitochondria.
R: Mitochondria are the powerhouse of the cell.
✅ Answer: (D) A is false but R is true.
10.
A: Breathing rate increases during exercise.
R: More oxygen is required to meet increased energy demands.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
11.
A: Arteries have thick and elastic walls.
R: They carry blood under high pressure from the heart.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
12.
A: Pulmonary veins carry deoxygenated blood.
R: All veins carry deoxygenated blood.
✅ Answer: (D) A is false and R is false.
13.
A: Valves in veins prevent backflow of blood.
R: Veins carry blood at low pressure toward the heart.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
14.
A: Xylem transports food in plants.
R: Xylem conducts water and minerals.
✅ Answer: (C) A is false but R is true.
15.
A: Transpiration helps in the upward movement of water in plants.
R: It creates a suction pull in the xylem.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
16.
A: Urea is produced in the kidneys.
R: Kidneys remove nitrogenous wastes from blood.
✅ Answer: (C) A is false but R is true.
17.
A: Nephrons are the structural and functional units of kidneys.
R: Nephrons help in filtration of blood and formation of urine.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
18.
A: Dialysis is done to treat kidney failure.
R: Dialysis removes waste and excess water from blood.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
19.
A: Excretion in plants is similar to that in animals.
R: Plants store excretory products in vacuoles and some are released through leaves.
✅ Answer: (C) A is false but R is true.
20
A: Sweating is a part of the excretory process.
R: Sweat contains water, salts, and urea.
✅ Answer: (A) Both A and R are true, and R is the correct explanation of A.
Digestive System – Assertion and Reason Questions
1.
A: Digestion of food starts in the mouth.
R: Saliva contains amylase that breaks down starch into sugar.
✅ Answer: (A)
2.
A: Proteins are digested in the mouth.
R: Saliva contains enzymes that break down proteins.
✅ Answer: (D)
3.
A: Hydrochloric acid is secreted in the stomach.
R: It creates an acidic medium necessary for the action of pepsin.
✅ Answer: (A)
4.
A: Bile is secreted by the liver and stored in the gallbladder.
R: Bile helps in emulsification of fats.
✅ Answer: (A)
5.
A: The pancreas secretes enzymes that digest all major food components.
R: Pancreatic juice contains amylase, trypsin, and lipase.
✅ Answer: (A)
6.
A: Small intestine is the site of complete digestion and absorption.
R: It has villi which increase the surface area for absorption.
✅ Answer: (A)
7.
A: Large intestine plays a major role in digestion of proteins.
R: It contains digestive enzymes like pepsin and lipase.
✅ Answer: (D)
8.
A: Peristalsis is the wave-like movement that pushes food forward in the alimentary canal.
R: It occurs in the esophagus, stomach, and intestines.
✅ Answer: (A)
9.
A: The stomach performs both mechanical and chemical digestion.
R: The stomach churns food and mixes it with gastric juice.
✅ Answer: (A)
10.
A: Digestion is completed in the stomach.
R: The stomach has all enzymes required for complete digestion.
✅ Answer: (D)
11.
A: Trypsin breaks down proteins into amino acids.
R: It is secreted by the pancreas and acts in the small intestine.
✅ Answer: (B)
12.
A: Lipase digests carbohydrates into simple sugars.
R: Lipase is secreted by the liver.
✅ Answer: (D)
13.
A: Villi are found in the stomach to aid in digestion.
R: Villi increase the surface area for absorption of digested food.
✅ Answer: (D)
14.
A: The small intestine is highly coiled to increase surface area.
R: A larger surface area ensures better absorption of nutrients.
✅ Answer: (A)
15.
A: The liver is involved in both digestion and excretion.
R: The liver produces bile and also detoxifies harmful substances.
✅ Answer: (A)
16.
A: The rectum is involved in digestion of undigested food.
R: It stores feces before elimination.
✅ Answer: (D)
17.
A: Pepsin requires an acidic medium to work.
R: HCl in the stomach maintains the acidic pH.
✅ Answer: (A)
18.
A: The esophagus performs digestion of food.
R: It secretes digestive enzymes and moves food by peristalsis.
✅ Answer: (C)
19.
A: Mucus protects the inner lining of the stomach.
R: HCl can damage the stomach walls if mucus is absent.
✅ Answer: (A)
20.
A: Pancreatic juice helps in digesting only proteins.
R: It contains only protease enzymes.
✅ Answer: (D)
Assertion and Reason Questions – Excretory System
1.
A: Kidneys filter waste products from blood.
R: Blood enters the kidney through the renal artery.
Answer: (A)
2.
A: Ureter carries urine from kidneys to the urinary bladder.
R: Ureter has valves to prevent backflow of urine.
Answer: (B)
3.
A: Urine is stored in the urinary bladder.
R: Urinary bladder expands to accommodate urine.
Answer: (A)
4.
A: Nephrons are present only in the kidneys.
R: Nephrons help in filtration and reabsorption.
Answer: (A)
5.
A: Urethra is longer in males than in females.
R: Urethra is used to excrete both urine and semen in males.
Answer: (A)
6.
A: Dialysis removes waste when kidneys fail.
R: Dialysis is an artificial kidney process.
Answer: (A)
7.
A: Glomerulus filters blood plasma.
R: Bowman’s capsule surrounds the glomerulus.
Answer: (A)
8.
A: Sweat contains water, salts, and urea.
R: Sweat glands help in temperature regulation.
Answer: (B)
9.
A: The liver is the main organ for excretion in humans.
R: Liver detoxifies harmful substances in the body.
Answer: (B)
10.
A: The kidneys produce urine continuously.
R: Urine is temporarily stored in the urethra.
Answer: (C)
11.
A: The renal vein carries filtered blood away from the kidney.
R: The renal artery carries unfiltered blood to the kidney.
Answer: (A)
12.
A: The nephron is the site for filtration only.
R: Reabsorption and secretion occur outside the nephron.
Answer: (C)
13.
A: Filtration occurs in the loop of Henle.
R: Loop of Henle helps in water reabsorption.
Answer: (D)
14.
A: Kidneys maintain the water-salt balance in the body.
R: Nephrons selectively reabsorb water and salts.
Answer: (A)
15.
A: Excretion helps maintain homeostasis.
R: Removing nitrogenous wastes prevents toxicity.
Answer: (A)
16.
A: The urethra in females carries only urine.
R: Females have separate reproductive and excretory openings.
Answer: (A)
17.
A: Urine contains glucose under normal conditions.
R: Glucose is reabsorbed in the nephron tubules.
Answer: (C)
18.
A: Excess water is excreted through sweat.
R: Sweating helps in thermoregulation.
Answer: (B)
19.
A: Renal artery carries oxygenated blood to the kidney.
R: Kidney cells require oxygen for metabolic activities.
Answer: (A)
20.
A: Filtrate formed in nephrons contains blood cells.
R: Filtration in glomerulus allows only small molecules to pass.
Answer: (D)
Assertion-Reason Questions – Respiration
1.
A: Respiration is the process of releasing energy from food.
R: Energy is released by the breakdown of glucose molecules.
Answer: (A)
2.
A: Aerobic respiration requires oxygen.
R: Oxygen helps in complete breakdown of glucose.
Answer: (A)
3.
A: Anaerobic respiration produces more energy than aerobic respiration.
R: Anaerobic respiration completely breaks down glucose.
Answer: (D)
4.
A: Breathing and respiration are the same processes.
R: Breathing is the intake of oxygen and respiration is the release of energy.
Answer: (C)
5.
A: Lactic acid is produced during anaerobic respiration in muscles.
R: Lactic acid causes muscle fatigue and cramps.
Answer: (A)
6.
A: Respiration occurs in all living organisms.
R: Energy is essential for all life processes.
Answer: (A)
7.
A: Carbon dioxide is released during respiration.
R: Carbon dioxide is a waste product of cellular respiration.
Answer: (A)
8.
A: Plants only perform photosynthesis, not respiration.
R: Plants release energy only during the day.
Answer: (D)
9.
A: Mitochondria are called the powerhouse of the cell.
R: Mitochondria are the site of respiration in cells.
Answer: (A)
10.
A: Oxygen debt occurs due to lack of oxygen during heavy exercise.
R: Oxygen debt causes lactic acid buildup.
Answer: (A)
11.
A: Alcohol is a product of anaerobic respiration in yeast.
R: Yeast respires anaerobically to produce alcohol and carbon dioxide.
Answer: (A)
12.
A: Respiration is only a catabolic process.
R: Respiration breaks down glucose to release energy.
Answer: (B)
13.
A: Plants release oxygen only during photosynthesis.
R: Plants respire and consume oxygen all the time.
Answer: (B)
14.
A: Anaerobic respiration in muscles produces carbon dioxide and water.
R: Anaerobic respiration occurs when oxygen is scarce.
Answer: (C)
15.
A: Breathing rate increases during exercise.
R: Muscles need more oxygen to release energy during exercise.
Answer: (A)
16.
A: Glucose is completely broken down in aerobic respiration.
R: Carbon dioxide and water are the end products of aerobic respiration.
Answer: (A)
17.
A: The trachea connects the lungs to the external environment.
R: Trachea is a part of the respiratory system.
Answer: (B)
18.
A: Energy released during respiration is stored as ATP.
R: ATP provides energy for various cellular activities.
Answer: (A)
19.
A: Respiration occurs only in animals.
R: Plants respire only during the day.
Answer: (D)
20.
A: Oxygen is the final electron acceptor in the electron transport chain.
R: Oxygen helps in forming water during respiration.
Answer: (A)
Assertion and Reason Questions – Transportation
1.
A: Xylem transports water from roots to leaves.
R: Xylem vessels are made up of dead cells forming continuous tubes.
Answer: (A)
2.
A: Phloem transports food from leaves to other parts of the plant.
R: Phloem vessels are made of living cells.
Answer: (A)
3.
A: Blood carries oxygen and nutrients to body cells.
R: Blood contains red blood cells that transport oxygen.
Answer: (A)
4.
A: Arteries carry oxygenated blood away from the heart.
R: Arteries have thick, elastic walls to withstand high pressure.
Answer: (A)
5.
A: Veins carry blood back to the heart.
R: Veins have valves to prevent backflow of blood.
Answer: (A)
6.
A: Capillaries connect arteries and veins.
R: Capillaries have thin walls to allow exchange of substances.
Answer: (A)
7.
A: The heart pumps blood throughout the body.
R: The heart has four chambers to separate oxygenated and deoxygenated blood.
Answer: (A)
8.
A: Lymph is a fluid that helps in transportation of nutrients.
R: Lymph also helps in fighting infections.
Answer: (A)
9.
A: Phloem transports only sugars.
R: Phloem transports sugars, amino acids, and hormones.
Answer: (C)
10.
A: Blood pressure is highest in veins.
R: Veins carry blood under low pressure.
Answer: (D)
11.
A: Plasma is the liquid part of blood.
R: Plasma carries hormones, nutrients, and waste products.
Answer: (A)
12.
A: Red blood cells do not contain a nucleus.
R: Lack of nucleus increases the oxygen-carrying capacity.
Answer: (B)
13.
A: Transportation in plants occurs only in xylem and phloem.
R: Water, minerals, and food are transported through xylem and phloem respectively.
Answer: (A)
14.
A: The left side of the heart pumps oxygenated blood.
R: The left ventricle has thicker walls than the right ventricle.
Answer: (A)
15.
A: Platelets help in blood clotting.
R: Platelets are fragments of larger cells called megakaryocytes.
Answer: (B)
16.
A: The human circulatory system is open.
R: Blood flows directly into body cavities in open circulatory systems.
Answer: (D)
17.
A: Transportation in plants is only upward.
R: Phloem transports food downward and upward.
Answer: (B)
18.
A: Deoxygenated blood enters the right atrium of the heart.
R: Right atrium pumps blood to the lungs for oxygenation.
Answer: (A)
19.
A: Water is transported in plants through active transport.
R: Water moves through xylem by transpiration pull.
Answer: (B)
20.
A: Veins have thin walls compared to arteries.
R: Veins carry blood at low pressure back to the heart.
Answer: (A)