Madhyamik Class 10 Life Science Solved Paper 2020

Madhyamik Life Science 2020 English Version (Unsolved) Flash Education

Madhyamik Class 10 Life Science Solved Paper 2020


Time: 3 Hours and 15 Minutes

(First 15 Minutes for reading the question paper only, 3 Hours for writing) 

Full Marks: For Regular Candidates – 90

For External Candidates – 100

Regular candidates will answer questions from Groups A, B, C and D. External candidates will answer questions from Group E.

(Special Instructions for visually handicapped candidates)

Answer Question 4.1(A) instead of Question 4.1 in Group D. Instruction on how many questions from a group must be attempted is provided at the beginning of the group.

Group ‘A’
(All questions are compulsory)

1. Choose the correct answer for each question and write it with its respective-serial number: [1 × 15=15]

Question 1.1

Select the correct pair-

  1. Cerebrum- Maintenance of balance of the body
  2. Hypothalamus-Control of intelligence and emotion
  3. Cerebellum-Control of body temperature
  4. Medulla Oblongata-Control of heartbeat and swallowing of food


Medulla Oblongata-Control of heartbeat and swallowing of food

Question 1.2

Identify which of the following statement is not true regarding Insulin-

  1. Helps in the absorption of glucose from the blood into most of the somatic cells
  2. Converts glucose into glycogen within liver and muscle cells
  3. Helps in the conversion of fat and protein into glucose
  4. Inhibits the conversion of protein and fat into glucose


Helps in the conversion of fat and protein into glucose

Question 1.3

Match the following words of column A with that of column B and select which of the following option is correct-
Column-A      Column-B
A. Flexion     (i) Quadriceps
B. Extension  (ii) Piriformis
C. Rotation    (iii) Biceps

  1. A-(i) B-(ii) C-(iii)
  2. A-(ii) B-(iii) C-(i)
  3. A-(iii) B-(i) C-(ii)
  4. A-(ii) B-(i) C-(iii)


A-(iii) B-(i) C-(ii)

Question 1.4

Determine from the answers given below which phases of karyokinesis during mitotic cell division following two incidents happen-

(A) Daughter chromosomes tend to move apart from each other towards their own poles

(B) Nuclear membrane and nucleolus disappear

  1. (A)Prophase (B) Anaphase
  2. (A)Anaphase (B) Prophase
  3. (A) Telophase (B) Metaphase
  4. (A) Metaphase (B) Telophase


(b) (A) Anaphase (B) Prophase

Question 1.5

Which of the following is the feature of cross-pollination-

  1. Occurs within the same flower of the same plant
  2. Agents are not required
  3. Lesser chance of new characters being transmitted
  4. More wastage of pollen grains


(d) More wastage of pollen grains

Question 1.6

Determine the number of DNA molecules that get coiled to form each chromosome in a newly formed daughter cell produced by mitotic cell division in the human body-

  1. 46
  2. 1
  3. 23
  4. Numerous


(b) 1

Question 1.7

Identify the genotype of Guinea pig having black colour and rough hair –

  1. BbRr, BBRr
  2. BBrr, Bbrr
  3. bbRR, bbRr
  4. bbrr, bbRr


(a) BbRr, BBRr

Question 1.8

Decide which of the following two were selected by Mendel as recessive traits –

  1. Colour of the follower-purple, Position of flower-axial
  2. Length of stem-dwarf, Form of ripe seed-wrinkled
  3. Form of ripe seed-round, Colour of seed yellow
  4. Position of flower-axial, length of stem-tall


(b) Length of stem – dwarf, form of ripe seed – wrinkled

Question 1.9

Assess from the following, the probable genotype parents having a haemophilic son and normal daughter-

  1. H||h, h|↑ 
  2. H||H, H|↑
  3. H||H, h|↑
  4. H||h, H|↑


(d) H||h,  H|↑

Question 1.10

Parthenium is an exotic species in our country. Other indigenous species cannot survive in such a place where it grows. This establishes one of the postulates of Darwin’s theory. Identify the postulate-

  1. Intraspecific struggle
  2. Interspecific struggle
  3. Struggle with environment
  4. Origin of species


(b) Interspecific struggle

Question 1.11

Miller and Urey, in their experiment, were able to synthesize some preliminary constituents necessary for the creation of life. Identify the ones which were amino acids among them-

  1. Lactic acid, Acetic acid
  2. Urea, Adenine
  3. Glycine, Alanine
  4. Formic acid, Acetic acid


(c) Glycine, Alanine

Question 1.12

Decide for which of the following purposes bees demonstrate waggle dance-

  1. search for reproductive mates
  2. Inform other worker bees about the direction and distance of the source of food from the bee hive
  3. selecting places for the construction of the new bee hive
  4. Avoid attack by probable enemy


(b) Inform other worker bees about the direction and the distance of the source of food from the bee hive

Question 1.13

Identify which of the following is the correct information related to biosphere reserve-

  1. Conservation is promoted to local people and other biotic communities along with the conservation of the ecosystem
  2. National parks and sanctuaries are not included in the biosphere reserve
  3. The presence and participation of local people in the conservation of the ecosystem are not permissible
  4. Its size is usually smaller than the Sanctuary


(a) Conservation is promoted to local people and other biotic communities along with the conservation of the ecosystem

Question 1.14

Decide which of the following pair is not correct-

  1. poaching-increase the endangeredness of gorilla
  2. Exotic Species-Lantana, Tilapia
  3. Determination of hotspot-Number of endemic species and endangered species
  4. Greenhouse gas-Eutrophication


(d) Greenhouse gas – Eutrophication

Question 1.15

Decide which of the following Tiger Projects is located within our state-

  1. Bandipore
  2. Simlipal
  3. Sundarbans
  4. Kanha


(c) Sunderbans

Group ‘B’

Answer 21 questions out of 26 questions given below as instructed. [1×21=21]

Question 2.1 – 2.6

Fill in the blanks (any five) [1 × 5=5]

  1. Acharya Jagdish Chandra Bose proved the property of ____ by sending electrical impulse in Mimosa and Desmodium plant.
  2. If gametes in human were produced by mitosis instead of meiosis then the number of autosomes in a somatic cell of an offspring would have been____.
  3. A disease in human population caused by recessive gene located in ‘X’ Chromosome is___.
  4. The hoof of modern horse is the transformation of the digital number____of ancestors.
  5. At the___ phase of nitrogen cycle ammonia is converted into nitrite and nitrate by the action of some bacteria.
  6. To produce the bottled cold drinks widely sold in the market, a lot of __ water is wasted.


  1. Sensitivity
  2. 88
  3. Haemophilia / Colour blindness
  4. 3rd
  5. Nitrification
  6. Ground/ Fresh/ Drinking

Question 2.2 – 2.6

Decide whether the following statements are true or false (any five) : [1 × 5=5]

  1. Tropic movement is the movement of growth in plants.
  2. Crossing over takes place during mitotic cell division.
  3. Mendel used the term gene while describing his experiment related to heredity.
  4. The leaf of the cactus is modified into the spine for the reduction of the rate of transpiration.
  5. Rhododendron is an endangered plant species conserved in the Eastern Himalaya hotspot.
  6. Choroid helps in the accommodation of the eye by changing the curvature and shape of the lens.


  1. True
  2. False. Crossing over is the exchange of genetic material between homologous chromosomes. It takes place during meiosis, not mitosis.
  3. False. Mendel did not use the term gene. He called the units of heredity “factors”. The term gene was coined by Wilhelm Johannsen in 1909.
  4. True
  5.  True
  6. False

Question 2.3

Match the words in column-A with the most appropriate words in column B and re-write the correct pair mentioning the serial no. of both columns (any five):-  [1 × 5=5]

Column A Column B
1. Gibberellin a) rrYY
2. Cutting b) Recharging of groundwater
3. Genotype of pea plant having
wrinkled and yellow colour seed
c) Pyrimidine base
4. Homologous organ d) Cause the breakdown of dormancy of bud
and seed
5. Wetland e) Structure is the same but work is different
6. Thymine and uracil f) RRYy
g) Rose


1 – (d), 2 – (g), 3 – (a), 4 – (e), 5 – (b), 6 – (c)

Question 2.4

Answer in a single word or in a single sentence (any six) [1 × 6=6]

  1. Chose the odd one and wrote it :
    Cerebrum, Hypothalamus, Pons, Thalamus
  2. Where the Schwann cells are located?
  3. A pair of related terms is given below. On the basis of the relationship in the first pair write the suitable word in the gap of second pair.
    Mitosis: Radicle : Meiosis: _____
  4. Which law did Mendel conclude from his dihybrid cross experiment?
  5. Give an example of a variation found among healthy persons which is transmitted through generations.
  6. How do Chimpanzees break open the hard shell for eating the nuts?
  7. Among the following four terms, one includes the other three, find out that term and write it: SPM, Air Pollution, Greenhouse gas, Lung disease.
  8. Name the practice which jointly the local peoples and forest department maintain for the reclamation of the forest.


  1. The odd one is Pons. The other three are parts of the forebrain, while the pons is part of the hindbrain.
  2. Schwann cells are located in the peripheral nervous system.
  3. Spore
  4. The law of independent assortment. This law states that the alleles of different genes assort independently of each other during meiosis.
  5. The ABO blood group is an example of a variation that is found among healthy persons and is transmitted through generations.
  6. Chimpanzees use stones to break open the hard shells of nuts. They will often carry a stone around with them and use it to crack open the nuts as they find them.
  7. The term that includes the other three is Air Pollution.
  8. The practice is called Joint Forest Management (JFM)

Group ‘C’

3. Answer any 12 questions in 2-3 sentences out of 17 questions given below: [2 × 12=24]

Question 3.1

Distinguish between the functions of hormones and the nervous system on the following parameters:

  • Nature of function
  • Place of function
  • Time span of function
  • fate


Hormone Nervous System
Nature of function Chemical Physical
Pace of Function Slow Fast
Time soan of function Long Short
Fate Inactive Unchanged

Question 3.2

‘A person can see distant objects distinctly but is unable to visualize near objects in a perfect way’- Predict what would be the probable cause and suggest the corrective measure for such a problem.


  • Cause – Flattened of eye ball.
  • Remedy – To use spectacle with a convex lens

Question 3.3

Analyse the role of synthetic plant hormones in increasing production and solving the problem of weeds in agriculture.


Synthetic plant hormones can be a valuable tool for increasing crop yields and solving the problem of weeds in agriculture. However, it is important to use them carefully and responsibly, as they can also have negative environmental impacts.

Question 3.4

‘LH or ICSH control the secretion of hormones of reproductive glands of the human body’ – judge the validity of the statement.


Partially valid. While LH (Luteinizing Hormone) and ICSH (Interstitial Cell-Stimulating Hormone) do play a role in controlling certain reproductive hormones, they do not solely control the secretion of all hormones in the reproductive glands.

Question 3.5

How can you distinguish between the mitosis of plant cells and that of animal cells on the basis of the formation of spindle fibre and the process of cytokinesis?


the key differences between mitosis in plant cells and animal cells, based on the formation of spindle fibres and the process of cytokinesis:

Spindle fibres

  • Plant cells: Plant cells do not have centrioles, so the spindle fibres form from the centrosomes, which are small, dense structures located in the cytoplasm.
  • Animal cells: Animal cells have centrioles, which are located near the nucleus. The spindle fibres form from the centrioles and extend towards the opposite poles of the cell.


  • Plant cells: In plant cells, cytokinesis occurs by the formation of a cell plate, which is a new cell wall that grows in between the two daughter cells.
  • Animal cells: In animal cells, cytokinesis occurs by the formation of a cleavage furrow, which is a groove that forms in the middle of the cell and eventually pinches the cell in two.

Question 3.6

Establish the relationship between the formation of malignant tumours in the human body with the loss of control in the cell cycle.


Due to loss of control of the cell cycle, the cell division takes place uncontrolled due to which numerous daughter cells are formed causing the formation of tumours. Such tumours cause cancer later on.

Question 3.7

‘The adventitious leaf bud plays a significant role in natural vegetative propagation of plant’ – Evaluate the validity of the statement with a proper example.


One example of a plant that utilizes adventitious leaf buds for natural vegetative propagation is the Bryophyllum plant. Bryophyllum produces adventitious buds along the margins of its leaves. When these leaves fall on the ground and come in contact with suitable conditions, such as moist soil, these adventitious buds develop into new plants with roots and shoots.

Question 3.8

Show with the help of the cross, who is more important among parents in determining the sex of their offspring.


sex determination

The father is more important than the mother in determining the sex of their offspring. This is because the sex of a child is determined by the sex chromosomes that are passed on from the parents. In humans, the sex chromosomes are X and Y. Females have two X chromosomes, while males have one X chromosome and one Y chromosome.

Question 3.9

‘Different genotypes produce the same phenotype’ – Justify the statement in the form a table by taking an example from the result of the dihybrid cross of the pea plant.


Round Yellow : Round Green Wringked Yellow









Question 3.10

Give your opinion about probable suggestion which can be given to a pair of contenders before marriage in order to prevent the spread of a genetic disease from the society already known to you.


Here are some suggestions that can be given to a pair of contenders before marriage in order to prevent the spread of a genetic disease from society:

  • Genetic counselling: This is a process where a couple can meet with a genetic counsellor to discuss their family history and the risk of passing on a genetic disease to their children. The counsellor can help the couple to understand the risks and options available to them.
  • Premarital genetic testing: This is a test that can be used to determine if a couple is a carrier of a genetic disease. If both partners are carriers, there is a risk that their child could be born with the disease.
  • In vitro fertilization: This is a procedure where eggs are fertilized in a laboratory and then implanted in the woman’s uterus. This can be used to select embryos that are not carriers of a genetic disease.

Question 3.11

A good number of Tilapia fishes are released in a pond having only different indigenous fish species grown naturally. Think and write which types of the struggle for existence Tilapia fishes have to face in order to survive.


Struggle for existence – Tilapia fishes have to face a struggle for existence for food and shelter among the fishes. The competition for food among different fishes in the pond will start. They have to face a struggle against the adverse physical and other conditions of the pond.

Question 3.12

Prepare a list of roles air sacs of pigeons play to fly in the air.


The roles air sacs of pigeons play to fly in the air are:-

  1. Airsacs reduce the specific gravity of the bird in the air.
  2. They naturally reduce friction during flight.
  3. They are helpful in reducing the body temperature.
  4. Help in dual respiration.

Question 3.13

Structure and function

Indicating the nature of evolution

Based on the above two features establish the concept of the analogous organ with the help of a proper example.


The two features that mentioned, structure and function, are important in defining analogous organs. The structure of an organ is its physical appearance, while the function of an organ is what it does. Analogous organs have similar functions, but they have different structures. This is because they evolved independently from each other.

Question 3.14

Relate the following phenomena with the trend of disturbance in the Nitrogen Cycle resulting from different human activities:

  1. Global Warming
  2. Acidification of soil and water of river and lake


Here are some ways in which global warming and acidification of soil and water can disturb the nitrogen cycle:

Global warming:

  • Increased temperatures can lead to changes in the rate of decomposition of organic matter, which can release more nitrogen into the atmosphere.
  • Higher temperatures can also lead to changes in precipitation patterns, which can affect the amount of nitrogen that is deposited in soils and water bodies.

Acidification of soil and water:

  • Acidification can make it difficult for plants to take up nitrogen, which can lead to a decrease in the amount of nitrogen available in the ecosystem.
  • Acidification can also damage the soil and water, making it more difficult for bacteria and other organisms to decompose organic matter and release nitrogen.

Question 3.15

Hilsa, Bee, Penguin, Rauwolfia- Asses which of the causes of endangeredness of the above-mention organisms.


Here are some of the causes of the endangeredness of Hilsa, bees, penguins, and Rauwolfia:


  1. Overfishing
  2. Habitat loss due to coastal development
  3. Pollution


  1. Colony collapse disorder
  2. Habitat loss due to agricultural intensification
  3. Pesticide use


  1. Climate change
  2. Overfishing
  3. Oil spills


  1. Overharvesting
  2. Habitat loss due to deforestation
  3. Competition from other medicinal plants

Question 3.16

Discuss any two roles of the People’s Biodiversity Register (PBR) in conserving local biodiversity.


People’s Biodiversity Register (PBR) :

  1. PBR promotes conservation.
  2. It motivates common people to create awareness about the management of natural resources.

Question 3.17

Tabulate any of the four activities which are prohibited in a sanctuary following the provisions of the Wildfire Act.


  1. Cutting of Trees.
  2. Killing of animals.
  3. Fishing
  4. Blowing of Motor horns

Group ‘D’

4. Answer 6 questions or their alternatives given below. [5×6=30]

Question 4.1

Draw a neat diagram of the vertical section of the eyeball of the human eye and label the following parts: [3+2=5]

  1. Choroid
  2. Optic nerve
  3. Iris
  4. Yellow spot


eye ball madhyamik


Draw a neat diagram of the metaphase of mitotic cell division in an animal cell and label the following art: [3+2=5]

  1. Chromatid
  2. Centromere
  3. Polar region
  4. Spindle fibre


Punete square 4

Question 4.2

Distinguish between mitotic and meiotic cell divisions in animals on the basis of the following features: [3+2=5]

  • Site of occurrence
  • Nature of Division of Chromosomes
  • The number of cells produces

List the changes in sense organs and bones that occurred during the senescence phase of human development.


Feature Mitosis Meiosis
Site of occurrence All cells of the body Germ cells only
Nature of division of chromosomes Equational division Reductional division
Number of cells produced 2 daughter cells 4 daughter cells
Crossing over No Yes

Here are some of the changes in sense organs and bones that occur during the senescence phase of human development:

Sense organs:

  • Vision: The lens of the eye becomes less elastic, which can lead to presbyopia, or difficulty seeing close objects.
  • Hearing: The hair cells in the inner ear become damaged, which can lead to hearing loss.


  • Bone mass: Bone mass decreases, which can lead to osteoporosis, a condition in which bones become weak and brittle.
  • Joints: The cartilage in joints wears down, which can lead to pain and stiffness.


Explain the importance of the following parts of a eukaryotic chromosome: 

  1. Centromere
  2. Telomere

Analyse the role of cell divisions in controlling growth, reproduction and repair in an organism. [3+2=5]


Here is the importance of the following parts of a eukaryotic chromosome:

(a) Centromere

  • The centromere is a specialized region of a chromosome that is responsible for the attachment of spindle fibres during cell division.
  • It is also important for the segregation of chromosomes during cell division, ensuring that each daughter cell receives the correct number of chromosomes.

(b) Telomere

  • Telomeres are the caps at the ends of chromosomes that protect them from degradation.
  • They also play a role in the regulation of cell division, as they shorten with each cell division.

Here is the role of cell divisions in controlling growth, reproduction and repair in an organism:

  • Growth: Cell division is essential for the growth of an organism. As cells divide, they increase in size and number, which allows the organism to grow larger.
  • Reproduction: Cell division is also essential for reproduction. Germ cells, such as sperm and eggs, are produced by cell division. These cells then fuse together to form a new organism.
  • Repair: Cell division can also help to repair damaged cells. When a cell is damaged, it can divide to produce new cells that are not damaged. This can help to prevent the spread of damage and to restore the function of the organism.

Question 4.3

Tabulate three pairs of dominant-recessive traits of pea plants as selected by Mendel. State the law of Mendel as deducted from the experiment of the Monohybrid cross. [2+3=5]


Here are three pairs of dominant-recessive traits of pea plants as selected by Mendel:

Trait Dominant allele Recessive allele
Flower colour Purple White
Seed shape Round Wrinkled
Seed colour Yellow Green

Mendel’s law of dominance states that when two alleles for a trait are different, the dominant allele will be expressed and the recessive allele will be masked. This means that if an individual inherits one dominant allele and one recessive allele for a trait, they will express the dominant trait.


A colour-blind female married a normal male. Judge the probability of colour blindness among their children in the first filial generation. Show with the help of a cross how the first law of Mendel has deviated in the case of the Four-O’ clock plant in F2 generation. [3+2=5]


Sex chromosome of Father – XY (Normal Male)

Sex chromosome of Mother – X°X (Colour Blind Female)

Male → Xo Y
Female ↓
Xo XoX XoY

50% of daughters will be colour-blind.

50% of daughters will be carriers of colour blindness.

The first law of Mendel, also known as the law of segregation, states that when two alleles for a trait are present in an individual, only one of the alleles will be expressed in the phenotype. The other allele will be hidden, or recessive.

Punete square 3 e1687544409897

R r
r Rr rr

The Four-O’clock plant is a good example of a deviation from the first law of Mendel. In this plant, the colour of the flower is determined by two alleles: R for red and r for white. When a plant that is homozygous for red (RR) is crossed with a plant that is homozygous for white (rr), all of the offspring in the F1 generation will be red. This is because the R allele is dominant over the r allele.

Question 4.4

With the help of arrow signs, show the major evolutionary events that occurred gradually after the origin of life.


Formation of Earth


Discuss the following three events as mentioned in the evolutionary theory of Darwin:

  • Prodigality of production
  • Origin of variation
  • Natural selection

‘Adaptation is the change of shape, physiological functions and behaviour of organism’- Justify the statement with the help of any two examples.


  • Prodigality of production: According to Darwin’s evolutionary theory, organisms tend to produce more offspring than can survive to adulthood. This excess production leads to competition for limited resources, as not all individuals can survive and reproduce successfully.
  • Origin of variation: Darwin proposed that variation exists among individuals within a population. This variation arises through mechanisms such as genetic mutations and genetic recombination during sexual reproduction. It is the raw material upon which natural selection acts.
  • Natural selection: Natural selection is the process by which certain heritable traits become more or less common in a population over time. Individuals with advantageous traits that increase their chances of survival and reproduction are more likely to pass on those traits to the next generation. This results in the gradual accumulation of beneficial traits in a population, leading to adaptation and evolution.

Question 4.5

Evaluate the effects of the following pollutants on the environment and human health: [1×5=5]

  1. Non-biodegradable insecticides
  2. Pollen grain
  3. Chemical fertilizers containing phosphate and nitrate
  4. Wastes containing pathogens originated from a health
  5. Chlorofluorocarbon


(a) Non-biodegradable insecticides

  • Environment: Non-biodegradable insecticides can persist in the environment for long periods of time, and they can accumulate in the food chain. This can have a negative impact on wildlife, as well as on humans who consume contaminated food.
  • Human health: Non-biodegradable insecticides can cause a variety of health problems, including cancer, reproductive problems, and neurological damage.

(b) Pollen grain

  • Environment: Pollen grain can be a nuisance, and it can also cause allergies in some people.
  • Human health: Pollen grain can trigger allergic reactions in some people, which can cause symptoms such as sneezing, coughing, and wheezing. In severe cases, allergies can lead to anaphylactic shock, which can be fatal.

(c) Chemical fertilizers containing phosphate and nitrate

  • Environment: Chemical fertilizers containing phosphate and nitrate can pollute waterways, leading to eutrophication. Eutrophication is a process in which excessive nutrients cause algae to grow out of control, which can lead to the death of fish and other aquatic life.
  • Human health: Chemical fertilizers containing phosphate and nitrate can also contaminate drinking water, which can lead to health problems such as kidney damage and cancer.

(d) Wastes containing pathogens originated from a health

  • Environment: Wastes containing pathogens can contaminate soil and water, which can lead to the spread of disease.
  • Human health: Wastes containing pathogens can cause a variety of diseases, such as cholera, typhoid, and dysentery.

(e) Chlorofluorocarbons (CFCs)

  • Environment: CFCs are ozone-depleting substances, which means that they can destroy the ozone layer. The ozone layer protects us from harmful ultraviolet radiation from the sun.
  • Human health: CFCs can also contribute to climate change.


Speculate the probable causes of each of the following phenomena: [1×5=5]

  1. Insomnia, High blood pressure, Partial or Complete deafness
  2. Decrease in the concentration of dissolved oxygen in the water and floating of dead fishes
  3. Decrease in the number of Crocodiles
  4. Inflammation in the respiratory tract of the lung
  5. Decrease in the number of pollinating insects


  1. Sound pollution
  2. Water pollution
  3. Water pollution
  4. Air pollution
  5. Use of Insecticides

Question 4.6

‘The ever-increasing population in the different cities of India is creating the crisis of groundwater’ – Support the statement with reasons on the basis of your experiences. Construct a concept map to show how the increase in human habitat is influencing the ecosystem of Sundarbans. [3 + 2 = 5]


The ever-increasing population in the different cities of India is creating a crisis of groundwater. It is due to the over-exploitation of natural resources and loss of the ecosystem.

Water resources are not sufficient on the earth for such a huge population. So, to fulfil the need of the population, the over-exploitation of natural resources started. Groundwater was used for irrigation, electric energy production and in functions on a large scale. Due to Global warming, the destruction of forests and plants, trees etc. Took place. As a result, natural unbalance, caused a disturbance in the regular Rain – cycle. The ever-increasing population affected the water ecosystem. Therefore, the water became polluted and a crisis of groundwater was created.

Increase in the habitat of People → Urbanization → Road making → Establishment of factories → Use of terrestrial lands → Deforestation → decrease in the habitat of plants and animals Loss of biodiversity Pollution unbalance of the ecosystem of Sunderban


Summarise which conservation measures have been adopted to increase the population of an endangered mammal exclusively found in the swampy grasslands under the foothills of the Easters Himalaya. Discuss the role of biodiversity in maintaining the balance of the ecosystem of a river. [3 + 2 = 5]


Here are some conservation measures that have been adopted:

  1. Establishment of protected areas: Protected areas such as national parks and wildlife sanctuaries have been established to protect the habitat of the hispid hare.
  2. Control of hunting and poaching: Hunting and poaching are major threats to the hispid hare, and conservation efforts have focused on controlling these activities.
  3. Reintroduction of captive-bred individuals: Captive-bred hispid hares have been reintroduced into the wild in an effort to increase the population.
  4. Public awareness: Public awareness campaigns have been launched to educate people about the importance of conserving the hispid hare.

Here are some of the roles of biodiversity in maintaining the balance of the ecosystem of a river:

  • Stabilizing river flows: Biodiversity helps to stabilize river flows by providing a variety of plants and animals that help to absorb and release water. This helps to prevent flooding and droughts.
  • Filtering pollutants: Biodiversity helps to filter pollutants from river water by providing a habitat for a variety of plants and animals that help to remove pollutants from the water. This helps to keep the water clean and safe for drinking and other uses.

Group – E

[For External Candidates Only]

5. Answer any four questions:- [1×4=4]

Question 5.1

Write one feature of epithelial tissue.


One feature of epithelial tissue is that it is avascular, meaning that it does not have its own blood supply.

Question 5.2

Which cell organelle is termed a ‘Suicidal Bag’?


The cell organelle that is termed a “suicidal bag” is the lysosome.

Question 5.3

Write one function of parenchyma tissue.


One function of parenchyma tissue is to produce and secrete substances.

Question 5.4

Give an example of an entomophilous flower.


An example of an entomophilous flower is a rose.

Question 5.5

Give an example of a proteolytic enzyme.


An example of a proteolytic enzyme is pepsin.

6. Answer any three questions:-[2×3=6]

Question 6.1

Write two differences between axon and dendron.


Two differences between axons and dendrites in table form:

Feature Axon Dendrite
The direction of signal transmission Away from the cell body Towards the cell body
Number One per neuron Many per neuron

Question 6.2

Write the name of two processes of plant excretion.


The two processes of plant excretion are:-

  1. Transpiration
  2. Excretion of waste products

Question 6.3

Write one function for each of the Mitochondria and plastids.


  1. Mitochondria: Mitochondria are the powerhouses of the cell, responsible for producing ATP, the cell’s energy currency.
  2. Plastids: Plastids are responsible for photosynthesis, the process by which plants convert light energy into chemical energy.

Question 6.4

Write the name of a National Park and a Biosphere Reserve of West Bengal.


  1. Buxa Tiger Reserve
  2. Gorumara National Park
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