Class 10 Science · Chapter 5

Life Processes

431 Class 10 Science questions on Life Processes from the NCERT textbook, NCERT Exemplar and CBSE board papers 2018–2026, each with its answer and a step-by-step solution.

CBSE Class 10 Science previous year papers, with answers →

Questions · page 8 of 22

1. Q141 CBSE 2026
   During the process of ​exhalation, air follows a ​definite path from lungs to ​outside. Choose ​the ​correct option showing the path ​of exhaled air.

   1. (a)Alveoli $⟶$ Trachea $⟶$ Larynx $⟶$ Pharynx $⟶$ Nostril
   2. (b)Nasal cavity $⟶$ Pharynx $⟶$ Larynx $⟶$ Trachea $⟶$ Bronchi $⟶$ Bronchioles
   3. (c)Body tissue $⟶$ Blood $⟶$ Lungs $⟶$ Nose
   4. (d)Alveoli $⟶$ Trachea $⟶$ Pharynx $⟶$ Larynx $⟶$ Nostril
   Show answer

   (a) Alveoli $⟶$ Trachea $⟶$ Larynx $⟶$ Pharynx $⟶$ Nostril

   Step-by-step solution →
2. Q142 CBSE 2026
   During sudden activity, cramps ​are caused ​in the ​muscles of legs in sports person. Choose the option ​that indicates the ​real cause of ​cramps.

   1. (a)Lack of oxygen and formation of carbon dioxide.
   2. (b)Presence of oxygen and formation of ethanol.
   3. (c)Lack of carbon dioxide and formation of pyruvate.
   4. (d)Lack of oxygen and formation of lactic acid.
   Show answer

   (d) Lack of oxygen and formation of lactic acid.

   Step-by-step solution →
3. Q143 CBSE 2026
   In ​human beings ​the ​oxygen ​rich blood ​is ​pumped out ​to ​the body by :

   1. (a)contraction of right atrium
   2. (b)relaxation of left ventricle
   3. (c)contraction of right ventricle
   4. (d)contraction of left ventricle
   Show answer

   (d) contraction of left ventricle

   Step-by-step solution →
4. Q144 CBSE 2026
   Opening of ​stomata ​is ​regulated ​by ​:

   1. (a)Entry of water into guard cells
   2. (b)Exit of water from guard cells
   3. (c)Entry of air into the stomatal pore
   4. (d)Entry of water into the stomatal pore
   Show answer

   (a) Entry of water into guard cells

   Step-by-step solution →
5. Q145 CBSE 2026
   Plants ​use variety of ​techniques to get rid of their waste ​materials. Some are mentioned below. Identify the ​incorrect ​one ​:

   1. (a)Excess water is given out by transpiration.
   2. (b)Gums and Resins are wastes that are stored.
   3. (c)Roots secrete some wastes into the soil.
   4. (d)Flowers can store some waste products.
   Show answer

   (d) Flowers can store some waste products.

   Step-by-step solution →
6. Q146 CBSE 2026
   Which ​of the ​following options ​is ​not a step in ​the process ​of photosynthesis ?

   1. (a)Absorption of light energy by chlorophyll
   2. (b)Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen
   3. (c)Reduction of carbon dioxide to carbohydrates
   4. (d)Storage of food in roots and stems
   Show answer

   (d) Storage of food in roots and stems

   Step-by-step solution →
7. Q147 CBSE 2026
   For the process ​of digestion, it is necessary to ​move ​the food in a regulated manner along ​the digestive tube, so that it ​can ​be processed properly in ​each part. The lining of ​the tube contracts rythmically which is known as :

   1. (a)Regulation
   2. (b)Absorption
   3. (c)Contraction
   4. (d)Peristalsis
   Show answer

   (d) Peristalsis

   Step-by-step solution →
8. Q148 CBSE 2026
   For Questions number 8 and 9, two statements are given — ​one labelled ​as Assertion ​(A) and ​the other labelled ​as Reason (R). ​Select ​the correct answer ​to these questions from the codes (a), (b), (c) and (d) as given below.

   Assertion (A): Blood plasma transports carbon dioxide in dissolved form, while oxygen is transported by respiratory pigments.

   Reason (R): Carbon dioxide is more soluble in water than in oxygen.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true, but Reason (R) is false.
   4. (d)Assertion (A) is false, but Reason (R) is true.
   Show answer

   (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).

   Step-by-step solution →
9. Q149 CBSE 2026
   For Questions number 8 and 9, two statements ​are given — one labelled as Assertion (A) and ​the other ​labelled as Reason ​(R). Select the correct answer ​to these ​questions ​from the codes (a), (b), (c) and (d) as given below.

   Assertion (A): Arteries have valves as they have to withstand high pressure.

   Reason (R): Arteries are vessels which carry blood away from the heart to various organs.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true, but Reason (R) is false.
   4. (d)Assertion (A) is false, but Reason (R) is true.
   Show answer

   (d) Assertion (A) is false, but Reason (R) is true.

   Step-by-step solution →
10. Q150 CBSE 2026
    For Questions number 8 and 9, two statements are ​given — one labelled as Assertion ​(A) ​and ​the other labelled as Reason (R). ​Select the correct answer to these questions from the ​codes (a), (b), (c) ​and (d) as ​given below.

    Assertion (A): Walls of the ventricles are thicker than those of the atria.

    Reason (R): Thick walls of the ventricles help in preventing the backflow of blood.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (c) Assertion (A) is true, but Reason (R) is false.

    Step-by-step solution →
11. Q151 CBSE 2026
    For Questions number 8 and 9, two statements are ​given — ​one labelled as Assertion (A) and the other ​labelled as Reason (R). Select the ​correct answer to ​these ​questions from the codes (a), ​(b), (c) and (d) as given below.

    Assertion (A): Mammals and birds have efficient supply of oxygen to the body.

    Reason (R): Mammals and birds have four-chambered heart.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).

    Step-by-step solution →
12. Q152 CBSE 2026
    For Questions number 8 and 9, two ​statements are given — one labelled as ​Assertion (A) and the other labelled as ​Reason ​(R). Select the correct answer to ​these questions from ​the codes (a), ​(b), (c) and ​(d) as given below.

    Assertion (A): Trachea does not collapse, even when there is no air in it.

    Reason (R): Trachea is supported by C-shaped ligament.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (c) Assertion (A) is true, but Reason (R) is false.

    Step-by-step solution →
13. Q153 CBSE 2026
    Directions : ​Question numbers 8 and 9 are Assertion and Reason based questions. Two statements ​are given, one labelled as Assertion (A) and the ​other is ​labelled ​as ​Reason (R). Select the correct answer to these questions from ​the codes (a), ​(b), (c) and (d) as given below :

    Assertion (A): In human beings, the respiratory pigment is haemoglobin present in red blood cells.

    Reason (R): Haemoglobin has a very high affinity for carbon dioxide.

    1. (a)Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    2. (b)Both, Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (c) Assertion (A) is true, but Reason (R) is false.

    Step-by-step solution →
14. Q154 CBSE 2026
    For ​Questions ​number 8 and 9, two statements are given — one ​labelled as Assertion (A) ​and ​the other labelled as Reason (R). Select ​the correct answer ​to ​these questions from the codes (a), (b), (c) and (d) as given below.

    Assertion (A): The basic filtration unit in the kidneys, like in the lungs, is a cluster of very thin-walled blood capillaries.

    Reason (R): Each capillary cluster in the kidney is associated with the cup-shaped end of a coiled tube called Bowman’s capsule.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

    Step-by-step solution →
15. Q155 CBSE 2026
    Question No. 8 & ​9 consists ​of two statements – Assertion ​(A) and ​Reason (R). Answer ​these questions ​selecting the appropriate option from ​(a), (b), ​(c) and (d) given below :

    Assertion (A): The peristaltic movements occur all along the gut.

    Reason (R): The lining of the gut has muscles that contract rhythmically to push the food in regulated manner.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

    Step-by-step solution →
16. Q156 CBSE 2026
    For Questions number 8 and 9, two statements are ​given — one labelled as Assertion (A) and the other ​labelled as Reason (R). ​Select ​the correct ​answer to these questions ​from ​the codes (a), (b), (c) and ​(d) as given below.

    Assertion (A): The lungs always contain a residual volume of air.

    Reason (R): The respiratory pigment is haemoglobin which has high affinity with ${\text{O}}_2$.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

    Step-by-step solution →
17. Q157 CBSE 2026
    "Transpiration in plants is ​a ​necessary evil." Comment ​on the statement giving ​two reasons.
    Show answer

    Transpiration is necessary (it pulls water up and cools leaves) but wasteful, as most absorbed water is lost and the plant may wilt.

    The statement is justified. Transpiration is **necessary** because (i) evaporation of water from the leaves creates the transpiration pull, the suction that draws water and dissolved minerals up the xylem from the roots to the top of the plant, and (ii) the water that evaporates carries heat away with it, cooling the leaves and protecting them from the sun. It is an **evil** because over $90\%$ of the water absorbed by the roots is lost as vapour, and when the loss outruns absorption the plant wilts and its growth suffers. The loss cannot be avoided, because the stomata that must open in daylight to admit carbon dioxide for photosynthesis are the same pores through which the water vapour escapes. A large, risky loss that the plant cannot do without is exactly a necessary evil.

    Step-by-step solution →
18. Q158 CBSE 2026
    What is the function of diaphragm in ​human respiratory ​system ? Where is ​it present ​in human body ​?
    Show answer

    The diaphragm is a muscular sheet below the lungs that changes the chest volume to draw air in and push it out.

    Position: The diaphragm is a dome-shaped sheet of muscle just below the lungs. It forms the floor of the chest (thoracic) cavity and separates it from the abdominal cavity. Function: It brings about breathing by changing the volume of the chest cavity. When it contracts and flattens, with the ribs lifted, the chest cavity enlarges, the pressure in the lungs falls and air is drawn in; when it relaxes and returns to its dome shape, the chest cavity becomes smaller and air is pushed out.

    Step-by-step solution →
19. Q159 CBSE 2026
    1. (a)Why is bile ​juice ​considered ​to be very important for digestion, even though ​it doesn’t contain any digestive enzymes ​?
    2. (b)Name ​some substances ​present in initial filtrate and ​subsequently selectively reabsorbed in the tubules of nephron.
    Show answer

    Bile makes the food alkaline and emulsifies fats; glucose, amino acids, salts and water are selectively reabsorbed in the tubules.

    (a) Bile juice has no enzymes, but it is essential for digestion because it makes the acidic food coming from the stomach alkaline, so that the pancreatic and small-intestinal enzymes can act, and its bile salts emulsify fats, breaking large fat globules into small droplets and so increasing the efficiency of the fat-digesting enzyme (lipase). (b) Glucose, amino acids, salts and a major amount of water are present in the initial filtrate and are selectively reabsorbed in the tubules of the nephron.

    Step-by-step solution →
20. Q160 CBSE 2026
    Give ​a ​diagrammatic ​representation ​of ​nutrition in ​Amoeba.
    Show answer

    Draw Amoeba four times to show ingestion by pseudopodia, digestion in the food vacuole, absorption and assimilation, and egestion.

    The answer is the labelled diagram shown above: one Amoeba drawn four times in a row. (i) Ingestion - the cell pushes out pseudopodia that surround the food particle. (ii) Digestion - the pseudopodia fuse, the food is enclosed in a food vacuole, and enzymes inside the vacuole break the complex food into simple soluble substances. (iii) Absorption and assimilation - the digested food passes from the vacuole into the cytoplasm and is used for energy, growth and repair. (iv) Egestion - the shrunken vacuole reaches the cell surface and the undigested residue is thrown out. Labels required: Amoeba, nucleus, food particle, pseudopodia, food vacuole, point of egestion.

    Step-by-step solution →